A lithium ore grade measurement based on the neutron & X-ray bi-modal imaging system.

The grades of the minerals significantly affects the energy consumption and chemical pollution along with the beneficiation process for extracting lithium element from the ores. Based on the large neutrons' macro cross section of the Li2O cluster inside the ores, the grades of lithium ores could be analyzed by the thermal neutron penetrating information. In this work, a bimodal imaging method, which utilizes both the information of penetrating neutrons and X-rays delivered by the same electron linear accelerator driven photoneutron system, was proposed to investigate the lithium concentration of each ore. A linearity R-square value of 0.991 between the results obtained with this method and those from the chemical method has been achieved. The average error in lithium concentration estimation is approximately 0.2 wt percent (wt%). The underlying principles and the experimental results will be elaborated on in this study.

Robust Thermal Neutron Detection by LiInP2 Se6 Bulk Single Crystals.

Direct neutron detection based on semiconductor crystals holds promise to transform current neutron detector technologies and further boosts their widespread applications. It is, however, long impeded by the dearth of suitable materials in the form of sizeable bulk crystals. Here, high-quality centimeter-sized LiInP2 Se6 single crystals are developed using the Bridgman method and their structure and property characteristics are systematically investigated. The prototype detectors fabricated from the crystals demonstrate an energy resolution of 53.7% in response to α-particles generated from an 241 Am source and robust, well-defined response spectra to thermal neutrons that exhibit no polarization or degradation effects under prolonged neutron/γ-ray irradiation. The primary mechanisms of Se-vacancy and InLi antisite defects in the carrier trapping process are also identified. Such insights are critical for further enhancing the energy resolution of LiInP2 Se6 bulk crystals toward the intrinsic level (≈8.6% as indicated by the chemical vapor transport-grown thin crystals). These results pave the way for practically adopting LiInP2 Se6 single crystals in new-generation solid-state neutron detectors.

A Design for the High Yield Photoneutron Source Target Station.

Low energy accelerator driven neutron sources are promising candidates to obtain a neutron yield as high as 1014 n/s, which is required for a variety of applications, such as boron neutron capture therapy, neutron imaging, and neutron scattering. The methods to generate neutrons can be divided into two categories: hadron-based and photon-based methods. In order to better understand which kind of source would be the better choice for delivering a brilliant neutron beam robustly, in this paper, the underlying principles of neutron production, as well as the simulation results of neutron yield, target heat dissipation, thermal stress, and reaction byproducts concentration of these two types of neutron sources, will be elaborated on. A preliminary photoneutron target station design based on a 50 MeV/50 kW electron linear accelerator, including the optimized neutron yield, thermal hydraulic analysis, and shielding calculation, is presented as well to demonstrate the method to deliver brilliant thermal neutron beam of 1.03 × 1010 cm-2 s-1 sr-1.

Molecular Imprinting Polymers Electrochemical Sensor Based on AuNPs/PTh Modified GCE for Highly Sensitive Detection of Carcinomaembryonic Antigen.

A novel molecular imprinted polymer (MIP) electrochemical sensor was successfully fabricated for sensitive detection of carcinomaembryonic antigen (CEA). We used CEA as template, dopamine (DA) as imprinted monomers. Through controlling electropolymerization, a "PDA-CEA"complex was achieved. After elution, the specific cavities adsorbed the target molecules. In addition, polythionine (PTh) and AuNPs were applied as the electrode modifying materials to enhance electron transfer rate and improve detection signal. Using differential pulse voltammetry (DPV) detection, the peak current decreased with the increase in concentration of CEA, and the linear response range of the MIP sensor was from 0.001 ng/mL to 1000 ng/mL with the detection limit as low as 0.2589 pg/mL. The MIP sensor had a low sample consumption, good stability, and high sensitivity, and could become a new promising method for the detection of CEA. Furthermore, this MIP sensor was demonstrated in testing CEA in human serum sample with satisfactory results.

Immunosensors Based on Nanomaterials for Detection of Tumor Markers.

Nanomaterials have been widely used to immobilize biomolecules, amplify the signals and concentrate the analytes for detection with good properties including large surface area, good adsorption capacity and high surface activity. In recent years, nanomaterials such as carbon nanomaterials, noble metal nanomaterials, polymers, are widely applied to research and develop immunosensors with high sensitivity and selectivity, which monitor the antigen-antibody reaction for the detection of tumor markers. This review provides an introduction of immunosensors and focuses on the design of electrochemical (EC) immunosensors, electrochemical luminscence (ECL) immunosensors and photoelectrochemical (PEC) immunosensors based on nanomaterials in nearly three years.