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Abstract The focal plane camera is the core component of the Wide Field-of-view Cherenkov/fluorescence Telescope Array (WFCTA) of the Large High-Altitude Air Shower Observatory (LHAASO). Because of the capability of working under moonlight without aging, silicon photomultipliers (SiPM) have been proven to be not only an alternative but also an improvement to conventional photomultiplier tubes (PMT) in this application. Eighteen SiPM-based cameras with square light funnels have been built for WFCTA. The telescopes have collected more than 100 million cosmic ray events and preliminary results indicate that these cameras are capable of working under moonlight. The characteristics of the light funnels and SiPMs pose challenges (e.g. dynamic range, dark count rate, assembly techniques). In this paper, we present the design features, manufacturing techniques and performances of these cameras. Finally, the test facilities, the test methods and results of SiPMs in the cameras are reported here.

The properties and structures of DLC films deposited by MEP-CVD using various gases CH4, HE/CH4, Ne/CH4 and Ar/CH4 are examined. The magnitude of effects on the properties for various inert gases was found as NE, Ar and He on the surface roughness was found as Ar, Ne and He.

The integrated photogrammetric mapping system flown on the last three Apollo lunar missions (AS15, AS16, and AS17) in 1971 and 1972 incorporated a Metric (mapping) Camera, a high-resolution Panoramic Camera, and a star camera and laser altimeter. The U.S. Geological Survey’s Astrogeology Science Center, the Intelligent Robotics Group of the NASA Ames Research Center, and Arizona State University are working together in an ongoing collaboration to achieve the most complete cartographic development of Apollo mapping system data into versatile digital map products. These will enable a variety of scientific/engineering uses of the data including mission planning, geologic mapping, geophysical process modelling, slope dependent correction of spectral data, and change detection. After a brief discussion of the origins of the mapping system, we describe the Metric and Panoramic cameras, processing of the associated image and support data, work to photogrammetrically control the Metric Camera images, and future plans.

Based on the medium-high resolution (R ∼ 20,000), modest signal-to-noise ratio (S/N ≳ 70) FLAMES-GIRAFFE spectra, we investigated the copper abundances of 129 red giant branch stars in the Galactic bulge with [Fe/H] from −1.14 to 0.46 dex. The copper abundances are derived from both local thermodynamic equilibrium (LTE) and nonlocal thermodynamic equilibrium (NLTE) with the spectral synthesis method. We find that the NLTE effects for Cu i lines show a clear dependence on metallicity, and they gradually increase with decreasing [Fe/H] for our sample stars. Our results indicate that the NLTE effects of copper are important not only for metal-poor stars but also for supersolar metal-rich ones and the LTE results underestimate the Cu abundances. We note that the [Cu/Fe] trend of the bulge stars is similar to that of the Galactic disk stars spanning the metallicity range of −1.14 < [Fe/H] < 0.0 dex, and the [Cu/Fe] ratios increase with increasing metallicity when [Fe/H] is from ∼−1.2 to ∼−0.5 dex, favoring a secondary (metallicity-dependent) production of Cu. [ABSTRACT FROM AUTHOR]

We present the chemical abundances of six stars in the halo stream Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)-N1, a new kinematically selected substructure from LAMOST data, from high-resolution spectra obtained with the Subaru/High Dispersion Spectrograph. Atmospheric parameters were determined by an iterative procedure based on spectroscopic analysis. Abundances of 11 elements, including α elements (Mg, Ca, Ti), odd-Z light elements (Na), iron-peak elements (Sc, Cr, Mn, Fe, Ni), and neutron-capture elements (Y, Ba), are measured by local thermodynamic equilibrium analysis procedures. [Fe/H] of the six stars ranges from −1.5 to −0.66. The abundance patterns of α elements show a similar trend to those of low-α stars in Nissen et al. and over 0.1 dex lower than those of Galactic field stars. The Sc, Cr, Mn, and Ni abundances of these six stars exhibit a positive trend with increasing iron abundance, with varying gradients. In addition, abundance distribution between [Na/Fe] and [Ni/Fe] and between that of [Ba/Y] and [Fe/H] of these six stars is different from both Galactic stars and the known dwarf galaxies. Our results suggest that LAMOST-N1 might be a relic of a system with slower chemical evolutions than the Milky Way. [ABSTRACT FROM AUTHOR]

We present chemical abundances of 15 stars in the γ Leo moving group based on high-resolution spectra with the Subaru High Dispersion Spectrograph. The sample was picked up by applying wavelet transform to UVW velocity components of stars in the solar neighborhood. Both photometric and spectroscopic method have been used to determine the stellar parameters of stars. Abundances of 11 elements including Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Y, and Ba are measured. Our results show that the member stars display a wide metallicity distribution with abundance ratios similar to Milky Way disk stars. We presume that the γ Leo moving group originated from dynamical effects that are probably related to the Galactic spiral arms. [ABSTRACT FROM AUTHOR]

The copper abundances of 29 metal-poor stars are determined based on the high-resolution, high-signal-to-noise ratio spectra from the UVES spectrograph at the ESO VLT telescope. Our sample consists of the stars of the Galactic halo, thick- and thin-disk, with [Fe/H] ranging from ∼−3.2 to ∼0.0 dex. The non-local thermodynamic equilibrium (NLTE) effects of Cu i lines are investigated, and line formation calculations are presented for an atomic model of copper including 97 terms and 1089 line transitions. We adopted the recently calculated photoionization cross sections of Cu i, and investigated the hydrogen collision by comparing the theoretical and observed line profiles of our sample stars. The copper abundances are derived for both local thermodynamic equilibrium (LTE) and NLTE based on the spectrum synthesis methods. Our results show that the NLTE effects for Cu i lines are important for metal-poor stars, in particular for very metal-poor stars, and these effects depend on the metallicity. For very metal-poor stars, the NLTE abundance correction reaches as large as ∼+0.5 dex compared to standard LTE calculations. Our results indicate that [Cu/Fe] is under-abundant for metal-poor stars (∼−0.5 dex) when the NLTE effects are included. [ABSTRACT FROM AUTHOR]

For the first time, we present an extensive study of stars with individual non-LTE (NLTE) abundances for 17 chemical elements from Li to Eu in a sample of stars uniformly distributed over the −2.62 ≤ [Fe/H] ≤ +0.24 metallicity range that is suitable for the Galactic chemical evolution research. The star sample has been kinematically selected to trace the Galactic thin and thick disks and halo. We find new results and improve earlier ones as follows: (i) the element-to-iron ratios for Mg, Si, Ca, and Ti form a metal-poor (MP) plateau at a similar height of 0.3 dex, and the knee occurs at common [Fe/H] ≃ −0.8. The knee at the same metallicity is observed for [O/Fe], and the MP plateau is formed at [O/Fe] = 0.61. (ii) The upward trend of [C/O] with decreasing metallicity exists at [Fe/H] < −1.2, supporting the earlier finding of Akerman et al. (iii) An underabundance of Na relative to Mg in the [Fe/H] < −1 stars is nearly constant, with the mean [Na/ Mg] ≃ −0.5. (iv) The K/Sc, Ca/Sc, and Ti/Sc ratios form well-defined trends, suggesting a common site of the K–Ti production. (v) Sr follows the Fe abundance down to [Fe/H] ≃ −2.5, while Zr is enhanced in MP stars. (vi) The comparisons of our results with some widely used Galactic evolution models are given. The use of the NLTE element abundances gives increased credit to the interpretation of the data in the context of the chemical evolution of the Galaxy. [ABSTRACT FROM AUTHOR]

We investigated the copper abundances of 64 late-type stars in the Galactic disk and halo with effective temperatures from 5400 to 6700 K and [Fe/H] from −1.88 to −0.17. For the first time, the copper abundances are derived using both local thermodynamic equilibrium (LTE) and non-local thermodynamic equilibrium (non-LTE) calculations. High-resolution (), high signal-to-noise ratio () spectra from the FOCES spectrograph are used. The atmospheric models are calculated based on the MAFAGS opacity sampling code. All the abundances are derived using spectrum synthesis methods. Our results indicate that the non-LTE effects of copper are important for metal-poor stars, showing a departure of ∼0.17 dex at a metallicity of . We also find that the copper abundances derived from non-LTE calculations are enhanced compared with those from LTE. The enhancements show clear dependence on the metallicity, which gradually increases with decreasing [Fe/H] for our program stars, leading to a flatter distribution of [Cu/Fe] with [Fe/H] than previous work. There is a hint that the thick- and thin-disk stars have different behaviors in [Cu/Fe], and bending of the disk stars may exist. [ABSTRACT FROM AUTHOR]

We present a new measurement of the α-spectroscopic factor (Sα) and the asymptotic normalization coefficient for the 6.356 MeV 1/2+ subthreshold state of 17O through the 13C(11B, 7Li)17O transfer reaction and we determine the α-width of this state. This is believed to have a strong effect on the rate of the 13C(α, n)16O reaction, the main neutron source for slow neutron captures (the s-process) in asymptotic giant branch (AGB) stars. Based on the new width we derive the astrophysical S-factor and the stellar rate of the 13C(α, n)16O reaction. At a temperature of 100 MK, our rate is roughly two times larger than that by Caughlan & Fowler and two times smaller than that recommended by the NACRE compilation. We use the new rate and different rates available in the literature as input in simulations of AGB stars to study their influence on the abundances of selected s-process elements and isotopic ratios. There are no changes in the final results using the different rates for the 13C(α, n)16O reaction when the 13C burns completely in radiative conditions. When the 13C burns in convective conditions, as in stars of initial mass lower than ∼2 M☼ and in post-AGB stars, some changes are to be expected, e.g., of up to 25% for Pb in our models. These variations will have to be carefully analyzed when more accurate stellar mixing models and more precise observational constraints are available. [ABSTRACT FROM AUTHOR]