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- 实验方案
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-ray suppression using artificial neural networks with the liquid scintillators BC-501A and BC-537
摘要： In this work we present a comparison between the two liquid scintillators BC-501A and BC-537 in terms of their performance regarding the pulse-shape discrimination between neutrons and γ rays. Special emphasis is put on the application of artificial neural networks. The results show a systematically higher γ-ray rejection ratio for BC-501A compared to BC-537 applying the commonly used charge comparison method. Using the artificial neural network approach the discrimination quality was improved to more than 95% rejection efficiency of γ rays over the energy range 150 to 1000 keV for both BC-501A and BC-537. However, due to the larger light output of BC-501A compared to BC-537, neutrons could be identified in BC-501A using artificial neural networks down to a recoil proton energy of 800 keV compared to a recoil deuteron energy of 1200 keV for BC-537. We conclude that using artificial neural networks it is possible to obtain the same γ-ray rejection quality from both BC-501A and BC-537 for neutrons above a low-energy threshold. This threshold is, however, lower for BC-501A, which is important for nuclear structure spectroscopy experiments of rare reaction channels where low-energy interactions dominates.
关键词： fast-neutron detection,BC-537,digital pulse-shape discrimination,liquid scintillator,BC-501A,neural networks
更新于2025-09-10 09:29:36
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Symmetric and asymmetric discrimination of bosonic loss: Toy applications to biological samples and photodegradable materials
摘要： We consider quantum discrimination of bosonic loss based on both symmetric and asymmetric hypothesis testing. In both approaches, an entangled resource is able to outperform any classical strategy based on coherent-state transmitters in the regime of low photon numbers. In the symmetric case, we then consider the low-energy detection of bacterial growth in culture media. Assuming an exponential growth law for the bacterial concentration and the Beer-Lambert law for the optical transmissivity of the sample, we find that the use of entanglement allows one to achieve a much faster detection of growth with respect to the use of coherent states. This performance is also studied by assuming an exponential photo degradable model, where the concentration is reduced by increasing the number of photons irradiated over the sample. This investigation is then extended to the readout of classical information from suitably designed photodegradable optical memories.
关键词： coherent-state transmitters,optical memories,bacterial growth,entangled resource,quantum discrimination,bosonic loss,Beer-Lambert law,photodegradable model,optical transmissivity,symmetric and asymmetric hypothesis testing
更新于2025-09-10 09:29:36
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-rays in liquid scintillation detectors by using low sampling frequency ADCs
摘要： It is well known that the digital pulse-shape discrimination (PSD) of fast neutrons and γ-rays in liquid scintillation detectors can be adversely affected by the low sampling frequency of the analog-to-digital converter (ADC). Previous studies have recommended that using an ADC with a sampling frequency of above 250 MHz is necessary to achieve a PSD performance comparable to that of the analog PSD systems. In the present study, we show that, in principle, a sampling frequency of above 32 MHz is sufficient to fully preserve the pulse-shape information of liquid scintillation detectors, though at such sampling frequencies a significant degradation of the PSD performance may arise from the used PSD algorithm. To avoid this problem, a new PSD algorithm in the frequency domain is presented and its excellent performance at low sampling frequencies is experimentally demonstrated. At the sampling frequency of 32 MHz, a Figure-of-Merit (FOM) of 1.31±0.04 in the light output range of 200-1400 keVee (electron equivalent energy) is achieved with an ADC of 10-bit resolution.
关键词： Digital Pulse-Shape Discrimination,Sampling Frequency,Analog-to-Digital Converter
更新于2025-09-10 09:29:36
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Discrimination of intact almonds according to their bitterness and prediction of amygdalin concentration by Fourier transform infrared spectroscopy
摘要： Intact almond kernels (N = 360, half sweet and half bitter) were analyzed using attenuated total re?ectance Fourier transform infrared spectroscopy (ATR-FTIR) for the prediction of amygdalin concentration and to classify them according to their bitterness. Amygdalin concentrations for sweet and bitter almonds, determined by high performance liquid chromatography, were between 0.7–350 and 15,000-50,000 mg kg?1, respectively. Concentrations were successfully predicted by applying partial least squares (PLS) to the pre-treated spectral data with R2p of 0.951 and RMSEP of 0.398. Additionally, linear discriminant analysis (LDA), quadratic discriminant analysis (QDA) and PLS-DA models were constructed to classify samples according to their bitterness. All three models provided a satisfactory discrimination of almonds into sweet and bitter categories, providing overall accuracy values of 83.3%, 86.1% and 98.6%, respectively. The results indicate the potential of ATR-FTIR spectroscopy for the reliable, easy and fast prediction of amygdalin concentration, and for almond classi?cation according to their bitterness.
关键词： Almond discrimination,ATR-FTIR,Bitterness,Intact almonds,PLS,Amygdalin concentration
更新于2025-09-10 09:29:36
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Multi-view Intact Discriminant Space Learning for Image Classification
摘要： Different views of one object usually represent different aspects of the object, and a single view is unlikely to comprehensively describe the object. In multi-view learning, comprehensive utilization of multi-view information is helpful. In this paper, we propose a novel supervised latent subspace learning method called multi-view intact discriminant space learning (MIDSL) by efficiently integrating complementary multi-view information of different views. MIDSL learns a latent intact discriminant space by employing Fisher discrimination criterion to fully use class label information, which can well guide exploiting useful discriminant information, of labeled training samples. MIDSL can simultaneously minimize the within-class scatter and maximize the between-class scatter of the feature representations of different objects in the learned latent intact discriminant space. Aiming to utilize unlabeled samples to help mining more useful information for better learning latent intact discriminant space, we extend MIDSL method in semi-supervised scenario and propose semi-supervised multi-view intact discriminant space learning (SMIDSL) method. We further extend MIDSL and SMIDSL methods by kernel technique and propose kernelized multi-view intact discriminant space learning (KMIDSL) and kernelized semi-supervised multi-view intact discriminant space learning (KSMIDSL) methods. Experimental results on Caltech 101, LFW, MNIST and RGB-D datasets demonstrate the effectiveness of our proposed methods.
关键词： Subspace learning,Image classification,Multi-view learning,Semi-supervised multi-view learning,Fisher discrimination criterion
更新于2025-09-09 09:28:46
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Crystal Growth and Scintillation Properties of YAG:Ce3+ for γ and α Detection
摘要： A bulk single crystal of yttrium aluminum garnet (Y3Al5O12:Ce3+, YAG:Ce3+) with good optical quality and free of cracks has been grown successfully by the Kyropoulos method. The dimension of the as grown crystal boule was ? 20 × 30 cm3. The cut and polished crystal sample of dimensions 1 × 1 × 0.5 cm3 was used for further measurements. The phase purity was confirmed by powder X-ray diffraction pattern analysis. The scintillation properties, such as X-ray emission spectrum, pulse height spectra, energy resolution, and scintillation decay time, were investigated using a 137Cs γ-ray source. The recorded X-ray emission spectrum shows a broad band between 500 and 700 nm with a peak at around 540 nm, which is attributed to the 5d-4f transition of the Ce3+ ion. The pulse-shape discrimination (PSD) of α and γ signals in a YAG:Ce3+ crystal has been studied by using different pulse shapes. The grown YAG:Ce3+ crystal which is non-hygroscopic, chemically inert, fast inorganic scintillator could be used for radiation detection application in nuclear, and high energy physics.
关键词： YAG:Ce3+ crystal,Kyropoulos method,Pulse shape discrimination,Radiation detector
更新于2025-09-09 09:28:46
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Discrimination of molecular thin films by surface-sensitive time-resolved optical spectroscopy
摘要： An optical discrimination technique, tailored to nanometric-sized, low optical absorbance molecular complexes adhering to thin metal films, is proposed and demonstrated. It is based on a time-resolved evanescent-wave detection scheme in conjunction with hierarchical cluster analysis and principal value decomposition. The present approach aims to differentiate among molecular films based on statistical methods, without using previous detailed knowledge of the physical mechanisms responsible for the detected signal. The technique is open to integration in lab-on-a-chip architectures and nanoscopy platforms for applications ranging from medical screening to material diagnostics.
关键词： time-resolved optical spectroscopy,principal value decomposition,optical discrimination technique,hierarchical cluster analysis,molecular thin films
更新于2025-09-09 09:28:46
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Optimal quantum-programmable projective measurement with linear optics
摘要： We present a scheme for a universal device which can be programed by quantum states to approximate a chosen projective measurement to a given precision. Our scheme can be viewed as an extension of the swap test to the instance where one state is supplied many times. As such, it has many potential applications given the variety of quantum information tasks which make use of the swap test. In particular, we show that our scheme is optimal for state discrimination under the one-sided error requirement, and optimally approximates any projective measurement. Furthermore, we propose a practical implementation of our scheme with passive linear optics, which involves a simple interferometer composed only of balanced beam splitters.
关键词： Hadamard interferometer,swap test,linear optics,state discrimination,quantum-programmable projective measurement
更新于2025-09-09 09:28:46
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Precise gas discrimination with cross-reactive graphene and metal oxide sensor arrays
摘要： Discriminating similar molecules remains a very challenging problem for semiconductor gas sensors. Here, we report a method to achieve precise gas discrimination of similar chemical vapors (mesitylene, o-xylene, and toluene) by using cross-reactive arrays consisting of metal oxide semiconductor and graphene sensors. It is dif?cult to identify these three chemicals as they have very similar responses to these sensors. Through cross-reactive Principal Component Analysis of the sensor response features, however, the discrimination accuracy improved from about 70% with a single gas sensor to almost 100% with the cross-reactive sensor array. Such a precise discrimination and the low-cost planar process make this approach a very attractive candidate for smart gas sensing and for future Internet of Things applications.
关键词： gas discrimination,metal oxide,sensor arrays,cross-reactive,graphene
更新于2025-09-09 09:28:46
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An ultrahigh spatial resolution radiation-imaging detector using 0.1 mm?×?0.1 mm pixelated GAGG plate combined with 1 mm channel size Si-PM array
摘要： Spatial resolution of a pixelated scintillator-based radiation-imaging detector is sometimes limited by the pixel size of the scintillators. We developed a small-size pixelated GAGG scintillator using a dicing method and combined it with a small channel-size Si-PM array for the development of an ultrahigh resolution radiation-imaging detector. The developed pixelated GAGG scintillator had a pixel size of 0.1 mm x 0.1 mm arranged in 0.15-mm separations. It was combined with a Si-PM array made of 1 mm x 1 mm channels to form a radiation-imaging detector. With the developed radiation imaging detectors, the 0.1 mm x 0.1 mm pixels could be resolved for Am-241 alpha particles (5.5 MeV). The spatial resolutions of this imaging detector were better than 0.31-mm FWHM for Am-241 alpha particles and Ca-45 (maximum energy: 0.24 MeV) beta particles. The spatial resolutions for Am-241 gamma photons (60 keV) and Cs-137 X-ray (~32 keV) were better than 0.6-mm FWHM. Separation of the images of alpha particles and gamma photons was possible using the scintillation decay time difference of GAGG between alpha particles and gamma photons. The developed ultrahigh spatial resolution pixelated GAGG radiation-imaging detector is promising for the imaging of alpha particles, beta particles, low-energy gamma photons and X-ray.
关键词： GAGG,ultrahigh spatial resolution,pulse-shape discrimination,pixelated,Si-PM array
更新于2025-09-04 15:30:14