[en] Using the Glauber theory and based on an independent alpha particle model, we have calculated the differential cross sections of π^---¹⁶O elastic scattering at three incident energies of the pion (T_π = 110, 180, 220 MeV). We have used two-body amplitude F_pialpha as the basic input to parametrize the semi-empirical equation. The parameters can be obtained by fitting the π-α elastic scattering data. Our results are in good agreement with the experimental data and the extent of agreement is comparable to that obtained in the previous optical potential calculations using pion-nucleon amplitude as input

[en] In ground-based cosmic ray experiments, the equalization of the transit time of signals coming from different parts of the apparatus is of crucial importance for the improvement of the angular resolution and accuracy. In the ARGO-YBJ experiment, this is achieved using the Characteristic Plane Method with conical correction, studied by both Monte Carlo simulation and real data and also checked with manual absolute calibration on a portion of the detector. By introducing conical correction in primary direction reconstruction, the systematics error existing in the off-line calibration with planar fit is successfully removed. Two subsequent construction phases of the detector have been considered: ARGO-42 and ARGO-104. During the calibration of ARGO-104, events with more than 1000 hits and with the core reconstructed inside the carpet were used in order to achieve a good reconstruction of the shower, that is the arrival direction and the core position. The results of the calibration concerning the two configurations, ARGO-42 and ARGO-104, are compared and discussed

[en] An Accelerator Driven System (ADS) project for nuclear waste transmutation has been launched by Chinese Academy of Sciences (CAS) since 2011. China LEAd-based Reactor (CLEAR) was selected as the reference reactor for the CAS ADS project and was designed and developed by Institute of Nuclear Energy Safety Technology (INEST), CAS. According to the research and development roadmap of CLEAR, a 10 MWth lead-bismuth cooled pool-type research reactor named CLEAR-I coupled with a proton accelerator will be constructed at the first stage. In order to verify the nuclear physics performances and the coupling techniques for the ADS system, a multifunctional lead-based zero power reactor (CLEAR-0) has been built, which is driven by a high intensity D-T fusion neutron generator (HINEG). A brief introduction on the design objective, experiment functions and system description for CLEAR-0 is given in this paper. The recent R&D progress on core design and coupling system is also presented. The first stage of CLEAR-0 is scheduled to couple with the first phase of HINEG and be finished for construction in the end of 2016, series of core characteristic experiments will be carried out in CLEAR-0. The testing data will be used to validate the calculation method, program and database used in the nuclear design, and also to support the safety analysis and license application for CLEAR-I. (author)

[en] Aim: Mutual information has currently been one of the most intensively researched measures. Despite the general promising results, it sometimes might lead to mis-registration because of neglecting spatial information and treating intensity variations with undue sensitivity. In order to avoid mis- registration and improve the robustness of algorithm, an extension of mutual information framework was proposed in which spatial information regarding higher-order image structures was incorporated into the registration processing of PET and MR. Fusion software of higher-order mutual information algorithm was developed and applied to PET and MR images of seven patients. Visual inspection and accuracy evaluation were also performed. Materials and Methods: The raw data of seven patients were provided by Vanderbilt University. Second-order entropy and normalized second-order mutual information were applied as similarity measures which integrate spatial information and avoid most local optima. PET image was treated as reference image while MR image as float image. Second-order entropy was calculated with 2D histogram measuring the frequency of co-occurrence of intensities between neighboring voxel pairs in a single image. The joint probability and second-order mutual information was estimated with the 4D histogram of the intensity of neighboring voxels between images. In order to avoid the occurrence of sparse histogram and simplify the computation, 16 bins per dimension were chosen in this project to calculate 4D joint histogram and the neighborhood was defined by the six nearest neighbors of each voxel. Optimization strategy was Powell's method, combined with Brent's algorithm. The interpolation method was PV method. Evaluation was carried out in a blinded fashion by Vanderbilt. Results: The mean of errors was 3.54mm and SE of which was 0.34. The registration accuracy was sub-voxel. Visual inspection showed that the image registrations of all the seven patients were good and no mis- registration occurred. Conclusion: The results demonstrate that sub-voxel registration accuracy has been achieved using the higher-order mutual information measure and that this algorithm is robust and insensitive to intensity variations. The higher-order mutual information also has a great potential in non-rigid registration, especially in image-guided surgery. The depression of intensity grades is the most primary one of all the factors that influence the accuracy. Carefully determination of float and reference image is surely important for registration with higher-order mutual information because the accuracy of this algorithm is also greatly affected by image resolution

[en] A wide field of view Cherenkov/fluorescence telescope array is one of the main components of the Large High Altitude Air Shower Observatory project. To serve as Cherenkov and fluorescence detectors, a flexible and mobile design is adopted for easy reconfiguring of the telescope array. Two prototype telescopes have been constructed and successfully run at the site of the ARGO-YBJ experiment in Tibet. The features and performance of the telescopes are presented.

[en] A contrastive research on two-proton (2p) emissions from excited states of the even-Z nucleus ²⁸S and its one-proton daughter, the odd-Z nucleus ²⁷P was performed by complete-kinematics measurements. The opening angles as well as relative momenta between two emitted protons and invariant masses of decaying systems were reconstructed through the event-by-event analysis of heavy fragments coincident with two protons. With the help of Monte Carlo simulations, results show a diproton-type decay with the branching ratio of 20₋₇⁺⁶% for ²⁸S while mainly three-body simultaneous decay in the phase space and/or 2p sequential emission for ²⁷P. Present results show that the diproton correlations may result from the proton configuration in the initial state like 2p skin/halo structure rather than the deformed orbit

[en] An experimental setup for low-energy nuclear astrophysics studies has been recently established at the Institute of Modern Physics (IMP), Lanzhou, China. The driver machine is a 320 kV high voltage platform, which can provide intense currents of proton, alpha and many heavy ion beams. The energy of a proton beam was calibrated against the nominal platform high voltage by using a well-known resonant reaction of ¹¹B(p,γ)¹²C and a non-resonant reaction ¹²C(p,γ)¹³N. The accuracy was achieved to be better than ±0.5 keV. The detection system consists of a Clover-type high-purity germanium detector, a silicon detector and a plastic scintillator. The performance of the detectors was tested by several experiments. The astrophysical S-factors of the ⁷Li(p,γ)⁸Be and ⁷Li(p,α)³He reactions were measured with this new setup, and our data agree with the values found in the literature. In addition, the upgrade of our driver machine and experimental setup has been discussed. As a future goal, a fascinating National Deep Underground Laboratory in China, the deepest underground laboratory all over the world, is prospected

[en] A large high-altitude air-shower observatory (LHAASO) is to be built at Shangri-La, Yunnan Province, China. This observatory is intended to conduct sub-TeV gamma astronomy, and as an important component of the LHAASO project, a water Cherenkov detector array (WCDA) is proposed. To investigate engineering issues and fully understand the water Cherenkov technique for detecting air showers, a prototype array at 1% scale of the LHAASO-WCDA has been built at Yang-Ba-Jing, Tibet, China. This paper introduces the prototype array setup and studies its performance by counting rate of each photomultiplier tube (PMT), trigger rates at different PMT multiplicities, and responses to air showers. Finally, the reconstructed shower directions and angular resolutions of the detected showers for the prototype array are given. -- Highlights: • The technique of the water Cherenkov array is studied. • Engineering issues of the water Cherenkov array are investigated. • The PMTs and electronics of the water Cherenkov array are tested. • Some key parameters of the water Cherenkov array are measured

[en] The low-energy astrophysical S factors of the ⁶Li(p,γ)⁷Be reaction have been investigated on a 320 kV platform at the Institute of Modern Physics in Lanzhou. The experimental S factor of this reaction shows an interesting sizable drop contrary to any existing theoretical expectations at energies below 200 keV. Such drop has not been fully understood yet and may reflect a novel reaction mechanism. The appearance of an interesting new positive-parity 1/2⁺ or 3/2⁺ resonance at E_c.m.≈195 keV is discussed. This study shows the danger of extrapolating experimental data over too large an energy range and demonstrates the need for careful direct experimental studies of reaction cross sections at or near stellar energies. In addition, our new results are discussed in the framework of a SUSY assisted Big-Bang Nucleosynthesis (BBN) model

[en] A gas-target system has been newly developed and installed at a Radioactive Ion Beam Line in Lanzhou (RIBLL), which makes RIBLL capable of delivering intense, low-energy RIBs for nuclear astrophysics studies. A 1.7×10⁴-pps intensity ²²Na RI beam has been achieved in a commissioning run. With further improvements, a 10⁵-pps intensity of some RI beams with mass A<30 (close to the line of β-stability) can be expected in the near future. Some detection equipment including Germanium and Silicon arrays (or balls) available (or to be constructed) at IMP are briefly introduced. A new low-energy radioactive beam line in China is now ready for nuclear astrophysics studies.