Skatole is one of the compounds responsible for the unpleasant odor found in tainted boar meat. Its quantification in blood plasma could allow for the identification of tainted carcasses for selective breeding or research purposes with measures in live animals. Toward this goal, we demonstrate that skatole may be quantified after extraction in blood plasma by electrochemiluminescence (ECL) using boron-doped diamond electrodes. First, a method for extracting skatole from plasma into acetonitrile for further analysis has been developed. Additionally, for the first time, native skatole has been detected in pig plasma samples using ECL for the determination of boar taint in pigs. A double extraction was achieved using an intermediate step with commercial rapeseed oil at a ratio of 1:4:10 (plasma/rapeseed oil/acetonitrile). Using standard solutions of deionized water spiked with skatole (50-1000 nM), a calibration curve demonstrated good linearity with a coefficient of determination (R 2) of 0.9948, a limit of detection of 37 nM (4.84 ng/mL), and a limit of quantification of 227 nM (29.69 ng/mL). Then, 24 pig plasma samples were analyzed, and the resulting skatole concentrations were compared with those contained in the fat of the same animals and determined using the "gold standard" technique, HPLC. The results reported here indicate a Pearson correlation coefficient (R 2) of 0.96. All of the pig samples that displayed an elevated skatole concentration above the consumer acceptance threshold can be identified from plasma analysis alone, thus demonstrating that plasma detection with ECL can be utilized for the determination of boar taint.

The aim of our study is to develop a material and associated detector that can provide a quantitative response when exposed to any kind of radionuclide decaying by the emission of alpha, beta, fast neutrons (thermalized by their environment or not) and/or gamma rays, accompanied with the categorization of such incoming radiation. To achieve this, only a single sensor is being used, composed of a three-layered, fully organic phoswich (a morphological stacking of different plastic scintillators) showing various thicknesses and decay times. The detection and sorting of fast, thermal neutrons and gamma-rays are obtained through a thick Li-6-doped scintillator. Beta and alpha detection and counting are performed respectively with thin and ultrathin films manufactured with dedicated thickness and decay times, optimized thanks to simulation studies. A Pulse Shape Discrimination method based on the charge comparison method is used to separate alpha, beta, neutrons and gamma rays contributions. We present the preparation and characterization of various configurations: quintuple discrimination, beta detection and alpha spectrometry (performed on a cocktail of alpha emitters). These experimental results are discussed and expended in the frame of complex multi-source scenarios. This all-purpose concept is trademarked as Omniscinti (TM).

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,717 new measurements from 869 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Most of the 120 reviews are updated, including many that are heavily revised. The Review is divided into two volumes. Volume 1 includes the Summary Tables and 97 review articles. Volume 2 consists of the Particle Listings and contains also 23 reviews that address specific aspects of the data presented in the Listings. The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print, as a web version optimized for use on phones, and as an Android app.

In the last decade, significant progress has been made in the development of plastic scintillators (PS) with effective neutron/gamma pulse shape discrimination (PSD). In this study, we investigate a plastic scintillator with remarkable neutron/gamma PSD properties for radon detection and alpha/beta PSD. The PS has outstanding alpha-/beta- PSD, energy resolution, and aging stability. It exhibits radon absorption properties with a diffusion length of 0.224(23) mm and a partition coefficient of 10.6(11) at 20(1) °C. We show how the absorption of radon can enhance studies on the alpha/beta PSD and energy resolution of plastic scintillators. Additionally, we introduce an improved peak shape model for the approximation of the PS’s alpha-particle spectrum of 222Rn and its short-lived decay products.

This work presents an outline of a detection system that employs the Compton spectrometer method to assess the non-linearity of scintillator light yield. A novel approach is introduced, leading to more accurate measurements through the separate determination of the intrinsic light output parameters and the non-linearity of the scintillators. Key features of this system include the use of a portable scintillation detector with three photomultiplier tubes for precise measurement of the average number of detected photoelectrons and the incorporation of recent advancements in correction techniques for accidental coincidences. The integration of digital acquisition, offline data analysis, and geometric adaptation reduces the time required to perform a measurement. The developed detector can simultaneously measure different timing properties, as well as the relative intensities following ionization excitation in a scintillator. The system’s performance is demonstrated through measurements of the light yield dependence on the deposited energy for commercially available liquid, plastic, and inorganic scintillators. Such instrumentation serves as a valuable tool in the development of novel scintillating materials, including liquid or solid organic scintillators, inorganic scintillators, and composite scintillators for electron detection, in addition to traditional X-ray or γ -ray detection.

L-tryptophan is an amino acid that is essential to the metabolism of humans. Therefore, there is a high interest for its detection in biological fluids including blood, urine, and saliva for medical studies, but also in food products. Towards this goal, we report on a new electrochemiluminescence (ECL) method for L-tryptophan detection involving the in situ production of hydrogen peroxide at the surface of boron-doped diamond (BDD) electrodes. We demonstrate that the ECL response efficiency is directly related to H2O2 production at the electrode surface and propose a mechanism for the ECL emission of L-tryptophan. After optimizing the analytical conditions, we show that the ECL response to L-tryptophan is directly linear with concentration in the range of 0.005 to 1 µM. We achieved a limit of detection of 0.4 nM and limit of quantification of 1.4 nM in phosphate buffer saline (PBS, pH 7.4). Good selectivity against other indolic compounds (serotonin, 3-methylindole, tryptamine, indole) potentially found in biological fluids was observed, thus making this approach highly promising for quantifying L-tryptophan in a broad range of aqueous matrices of interest.

Homogenous radioactive gas contamination constitutes the hardest challenge for radioprotection due to its elusive nature. Most common radioactive gas are 85 Kr, 222 Rn, and tritiated ( 3 H) vapors. Each of them has different challenges, often leading to specialized single‐gas detectors. The state‐of‐the‐art detection either produces chemical‐radiological waste, is hard to implement online, or requires large volume. A new paradigm is presented for radioactive gas detection that can perform online detection on any gas and fit in the hand. This study use photoluminescent metal organic frameworks (MOFs) as both porous gas sponges and scintillators. The response of several zinc based MOF is studied, using a unique radioactive gas test bench. These tests showed that MOFs are able to both concentrate and detect successfully 85 Kr. The investigation is completed with calibration with different activities. The study also reports detection of 222 Rn, and measurement of its half‐life. Finally, the study is completed with the successful detection of tritiated dihydrogen, commonly known to be a hard radionuclide to detect due to its low energy and penetration range. This paper shows that scintillating MOFs are a powerful solid‐state approach and a practical solution to the challenge of radioactive gas measurements.

This work presents a new system dedicated to the measurement of energy spectra from radionuclide-based neutrons sources (ex. AmBe, PuBe, 252 Cf). The experimental device consists of a large-volume polyethylene container that is equipped with a central channel accommodating the source to be measured and 12-measurement channels (in a spiral formation) around the source, into which detectors can be placed. The container is filled with water in order to moderate neutrons emitted from the source and to reduce the sensitivity of the detectors to the external environment. Measurements have been performed with 6 Li-doped plastic scintillators (PS) developed in-house and optimized for the simultaneous detection of fast neutrons, thermal neutrons, and gamma rays, through signal processing based on Pulse Shape Discrimination (PSD). This novel approach solves the underdetermined problem as observed in the case of classical neutron spectrometers (ex. Bonner sphere systems with limited experimental data). Through the use of 6 Li-doped PS information, the increased experimental data enable the spectrum of interest to be recreated without the need to introduce a "default spectrum" in the unfolding process. The reconstruction is performed with an iterative Maximum-Likelihood Expectation–Maximization algorithm (ML-EM) throughout the detector's responses matrix calculated with the MCNP6 code. An optimized version of this ML-EM algorithm with a regularization step has been also tested. The design, methodology and preliminary results are presented. Different types of neutron sources were measured and results are consistent, with a clear benefit when using experimental data taking into account the measured fast neutron component instead of using only thermal neutron counting.

A new method for the determination of skatole present in porcine adipose tissue samples utilizing the electrochemiluminescence of skatole is presented. It has been observed that oxygen radicals produced at a high cathodic voltage can react with oxidized skatole to create an excited intermediate molecule that then relaxes, generating peak photon emission at around 480 nm. A strong electrochemiluminescence or electrogenerated chemiluminescence (ECL) signal using boron-doped diamond (BDD) electrodes was observed optimally when a reduction potential of -1.8 V was applied, held for 40 s, before holding an oxidation potential of 0.8 V for 10 s. Using this principle, a calibration curve using known concentrations of skatole showed good linearity (range 0.025-2 μM) and a very low detection limit (LOD, 0.7 nM). A method that demonstrates for the first time an approach that utilizes this ECL reaction, and has the potential to be developed into an analytical device for use in the slaughterhouse, has been developed. This was achieved by extracting skatole out of the porcine adipose tissues into acetonitrile - giving an extraction efficiency of 67.6%. This method was then validated by analyzing the skatole content of 33 pig fat samples that had been previously tested using a standard technique, high-performance liquid chromatography (HPLC), containing a range of concentrations (0.02-2.58 μg/g). This ECL method exhibited excellent reliability and correlation with HPLC, giving a R2 coefficient of 0.911, thus demonstrating the potential for this method to be developed for an on-line skatole detector.

We report the investigations made on the use of pixelated plastic scintillator (PS) and silicon photomultipliers (SiPMs) array applied to coded aperture gamma-neutron imaging. Specifically, verification of the ability of a multiplexing readout to discriminate and localize neutron interactions was studied. In its intended configuration, the gamma-neutron imager design consists of a coded aperture aligned with a matrix of $12\times12$ PS each coupled to a SiPM. The coded aperture is a rank 7 modified uniformly redundant array (MURA), composed of 1.2 cm of tungsten, with a surface area of 100.4 mm $\times100.4$ mm and placed at 5 cm from the detector. The pixelated PS is composed of polystyrene and standard fluorophores (20 wt% PPO, 0.03 wt% POPOP) loaded with a lithium carboxylate (Li $\alpha $ -valerate), which allows the triple discrimination between thermal neutrons, fast neutrons, and photons. Each pixel of PS has a dimension of 3.6 mm $\times3.6$ mm $\times3.6$ mm and they are separated from each other by 0.6 mm of polytetrafluoroethylene (PTFE). The photonic and electronic readout consists of the ArrayC-30035-144P SiPM from SensL, Cork, Ireland, connected to the diode coupled charge division readout from AiT. First, this neutron imager design was modeled and simulated using the MCNP6 Monte Carlo code. The encoding capability, field of view, and spatial resolution of the neutron imager were therefore evaluated by simulation. Then, we detailed the experimental setups implemented to demonstrate the feasibility of coupling pixelated PS to SiPM to localize radioactive sources and showed the results obtained. Finally, based on this position-sensitive gamma-neutron detector, a gamma-neutron imager was prototyped and tested.

The development of plastic scintillators loaded with low-cost phosphorescent sensitizer is currently an important topic toward enhancing the scintillation light yield for radiation detection applications. In this work, we report plastic scintillators loaded with deep-blue-emitting phosphorescent sensitizer CuI(PPh3)2(t-BuPy), where PPh3 and t-BuPy stand for triphenylphosphine and 4-tert-butylpyridine, respectively. CuI(PPh3)2(t-BuPy)-loaded poly(vinyltoluene)-based plastic scintillators with high optical transmittance of over 80% were synthesized via bulk polymerization method. The optical absorption, photoluminescence spectra, decay kinetics, and scintillation performance under X-ray, γ-ray, and α-particle excitation were comprehensively investigated. The scintillation yield was reduced with the increase of CuI(PPh3)2(t-BuPy) loading concentration. The physical mechanism and the role of the copper iodide complex in scintillation yield reduction are proposed.

Radiological detection where Cherenkov residual background can be prominent requires scintillators with increased emission wavelength. Cherenkov residual background precludes the use of UV-emitting sensors such as plastic scintillators. However, the literature is scarce in red-emitting plastic scintillators and only one commercial scintillator is currently available (BC-430, from Saint-Gobain Crystals and Detectors). In addition, X-ray imaging or time-of-flight positron emission tomography (ToF-PET) applications are also demanding on this type (color) of scintillators, but such applications also require that the material displays a fast response, which is not particularly the case for BC-430. We present herein our latest developments in the preparation and characterization of fast and red plastic scintillators for this application. Here, ‘fast’ means nanosecond range decay time and ‘red’ is an emission wavelength shifted towards more than 550 nm. At first, the strategy to the preparation of such material is explained by decomposing the scintillator to fundamental elements. Each stage is then optimized in terms of decay time response, then the elemental bricks are arranged to give plastic scintillator formulations that are compatible with the abovementioned characteristics. The results are compared with the red-emissive BC-430 commercial plastic, and the ultra-fast, violet-emitting BC-422Q 1% plastic. In particular, the first-time use of trans-4-dimethylamino-4′-nitrostilbene in the scintillation field as a red wavelength shifter allowed preparing plastic scintillators with the following properties: λemmax 554 nm, photoluminescence decay time 4.2 ns, and light output ≈ 6100 ph/MeV. This means a scintillator almost as bright as BC-430 but at least three times faster. This new sensor might provide useful properties for nuclear instrumentation.

Nowadays, Thermally Activated Delayed Fluorescence (TADF) compounds have proven to be attractive for highly efficient optoelectronic devices as they can exploit both singlet and triplet excited states generated by charge recombinations that occur in such devices. However, quenching of excited states limits such benefits at high current densities. We have studied the quenching in the case of cationic copper(I) complexes coordinated by both N-heterolytic carbene (NHC) and 2,2'-dipyridylamine (dpa) ligands. Defects are created in their crystals by a strong laser irradiation. Then we have investigated, by analysing their fluorescence decay as a function of temperature, the quenching mechanism and the exciton mobility. Using a time-resolved version of the Perrin's quenching model, we show that the quenching volume depends on temperature according to the singlet/triplet equilibrium. At room temperature, the singlet states are responsible for 75% of the quenching although they contribute for 2% to the excited states population. From the analysis of the decay curves, we show that the excitons are not mobile in the crystals and are quenched through Forster Resonant Energy Transfer (FRET).

The characterization of a scintillating metal organic framework (MOF) is not straightforward, mainly due to the small size and low density of the material. In this context, we present herein a generic method to give an easy access to the determination of a key parameter in the scintillation field, namely the light output. To reach this, MOF‐205 was first synthesized as millimetric‐size single crystals then sintered under pressure and temperature conditions to afford a pellet. The density was increased by 300% while maintaining optical properties on par with scintillation application. The as‐prepared scintillator was then characterized in terms of photoluminescence (PL; UV‐excited emission spectrum, time‐correlated single photon counting) and radioluminescence (RL) spectroscopy (beta‐excited emission spectrum, alpha, beta and gamma pulse height spectra, alpha/beta and alpha/gamma discrimination). Results were compared with commercial BC‐404 plastic scintillator performances as well as supported by MCNP6.2 simulation.

Several particle-physics experiments use poly(methyl methacrylate) (a.k.a. PMMA or acrylic) vessels to contain liquid scintillators. Superluminal charged particles emitted from radioactive impurities in or near the acrylic can emit Cherenkov radiation in the ultraviolet (UV) spectra range. If acrylic fluoresces in the visible range due to this UV light, it could be a source of background in experiments where the main signal is visible scintillation light, or UV scintillation light that is absorbed and re-emitted at visible wavelengths by a wavelength shifter. Some of these experiments operate at low temperature. The fluorescence of these materials could change with temperature so we have studied the fluorescence of the acrylic used in the DEAP-3600 experiment down to a temperature of 4 K, and compared it to the common wavelength shifter 1,1,4,4-tetraphenyl-1,3-butadiene (TPB). The light yield and wavelength spectra of these materials were characterized by exciting the sample with 285 nm UV light, which acted as a proxy for Cherenkov light in the detector. Spectral measurements indicate at least part of the fluorescence of the acrylic is due to additives. Time-resolved measurements show the light yields of our acrylic sample, TPB sample, and the relative light between both samples, all increase when cooling down. At room temperature, the light yield of our acrylic sample relative to the TPB sample is 0.27%, while it reaches 0.48% at 4 K. The main fluorescence time constant of the acrylic is less than a few nanoseconds.

The paper introduces new developments in the conception, optimization, and principle validation of a neutron counter, based on the insertion of gadolinium in plastic scintillators, that is under work at CEA LIST since 2017. The radiation sensor, comprising two volumes of scintillating polymers, it is, by nature, sensitive to both neutron and gamma radiations. This allows the design of a versatile n/gamma detector, provided that it is possible to algorithmically separate the signature of both types of radiations. After amplitude and gamma-gamma coincidence filtering, the authors investigate a third n/gamma discrimination mode by proton-gamma temporal correlation filtering. After a bibliographic study, the article details the estimation of the temporal parameter useful for such a discrimination, firstly by explicit calculations, secondly by means of a MCNP6.1-based, dedicated simulator. A time-based-processing firmware, embedded into a pulse acquisition card, was then created to compare these estimates with experimental distributions. A 50-mu s temporal gate was identified as relevant to discriminate temporal correlations in presence of a neutron emitter. A compensation technique was eventually implemented in order to obtain first experimental estimates of neutron sensitivity, and neutron detections limits in a mixed field. The study ends up providing a maximum reachable sensitivity in the order of 0.3 c.n(-1).cm(2) under a fast neutron flux (AmBe), with two 1-L plastic scintillators separated by a 250-mu m Gd converter, and the associated temporal correlation and compensation algorithm, as well as neutron detection limits in the same order as those of a He-3 Bonner sphere over acquisition times between 1 and 10 min.

The development of highly efficient plastic scintillators for neutron/gamma pulse shape discrimination is a matter of current interest. This is generally achieved using two fluorophores, with one of them being added to the polymer formulation at a concentration higher than typically 15 weight percent (wt%). Here, we report our results concerning the development of highly performant poly(vinyltoluene)-based (PVT) plastic scintillators for efficient fast neutron/gamma pulse shape discrimination, using 1-phenyl-3-(mesityl)-2-pyrazoline (1) as the only guest fluorophore. On our route during this study, the synthesis of the compound 1 has been revisited. Analysis and evaluation of the radioluminescence properties of these novel PVT-based plastic scintillators containing compound 1 are also described. In particular their light output and neutron/gamma discrimination ability were characterized. The sample doped with 15 wt% of compound 1 has a light output of 0.65 relative to EJ-200 and a neutron/gamma discrimination figure of merit of 0.84 in the range 450–500 keVee.

Three aryl methyl sulfoxides were prepared via the following sequence: synthesis of the menthyl arenesulfenate from the corresponding thiol, diastereoselective oxidation leading to the sulfinate, then reaction with a Grignard reagent. The aryl moiety was substituted with a methyl ester on the ortho position or a nitro group on the ortho or the para position. The sulfenate esters were obtained in fair to excellent yield (42–82%). Four different oxidizing agents were tested to obtain the corresponding sulfinate esters with diastereomeric excesses (de) ranging from 10 to 48%. After separation of the diastereomers and reaction with methyl Grignard reagent, two enantiopure sulfoxides and one enantioenriched sulfoxide (32% ee) were obtained.

In this chapter, we present an overview of the field of plastic scintillation through a chemical point of view. More particularly, we focus on their design by the homogenous incorporation of organometallic dopant in the wide sense of the term. This chapter is organized into sections representing the main application and the associated choice of metal dopant. We present and evaluate in these contexts different chemical strategies, focusing on the inherent tradeoff that come with loading a plastic scintillator with organometallics. Examples of applications and successful transfers are also shown to motivate and encourage the community to explore this field.