We propose to build a large water-Cherenkov-type muon-detector array (Tibet MD array) around the 37,000 m 2 Tibet air shower array (Tibet AS array) already constructed at 4,300 m above sea level in Tibet, China. Each muon detector is a waterproof concrete pool, 6 m wide × 6 m long × 1.5 m deep in size, equipped with a 20 inch-in-diameter PMT. The Tibet MD array consists of 240 muon detectors set up 2.5 m underground. Its total effective area will be 8,640 m 2 for muon detection. The Tibet MD array will significantly improve gamma-ray sensitivity of the Tibet AS array in the 100 TeV region (10-1000 TeV) by means of gamma/hadron separation based on counting the number of muons accompanying an air shower. The Tibet AS+MD array will have the sensitivity to gamma rays in the 100 TeV region by an order of magnitude better than any other previous existing detectors in the world. Keywords Gamma ray · Cosmic ray · Muon · SNR PACS 95.55.Ka · 98.70.Sa · 95.85.Ry

Photosynaptic organic field‐effect transistors (OFETs) represent a viable pathway to develop bionic optoelectronics. However, the high operating voltage and current of traditional photosynaptic OFETs lead to huge energy consumption greater than that of the real biological synapses, hindering their further development in new‐generation visual prosthetics and artificial perception systems. Here, a fully solution‐printed photosynaptic OFET (FSP‐OFET) with substantial energy consumption reduction is reported, where a source Schottky barrier is introduced to regulate charge‐carrier injection, and which operates with a fundamentally different mechanism from traditional devices. The FSP‐OFET not only significantly lowers the working voltage and current but also provides extraordinary neuromorphic light‐perception capabilities. Consequently, the FSP‐OFET successfully emulates visual nervous responses to external light stimuli with ultralow energy consumption of 0.07–34 fJ per spike in short‐term plasticity and 0.41–19.87 fJ per spike in long‐term plasticity, both approaching the energy efficiency of biological synapses (1–100 fJ). Moreover, an artificial optic‐neural network made from an 8 × 8 FSP‐OFET array on a flexible substrate shows excellent image recognition and reinforcement abilities at a low energy cost. The designed FSP‐OFET offers an opportunity to realize photonic neuromorphic functionality with extremely low energy consumption dissipation.

We present high spatial resolution ALMA observations of vibrational transitions of HC3N toward Orion KL in the 214–247 GHz frequency band. 41 transitions of HC3N in 7 vibrationally excited states, and 23 transitions of 13C isotopologues of HC3N in 2 vibrational states are detected. The line images show that vibrationally excited HC3N lines originate mainly from the hot core of Orion and IRc7. The images of HC3N vibrationally excited lines show that the line emission peaks associated with the hot core move from south to northeast as increases. Based on multiple transitions of each vibrationally excited state, we performed local thermodynamic equilibrium calculations in the XCLASS suite toward the hot core and IRc7 positions. Generally, transitions in highly excited states have higher rotational temperatures and lower column densities. The rotational temperatures and column densities of the hot core range from 93 to 321 K, and from to cm−2, respectively. Lower rotational temperatures ranging from 88 to 186 K and column densities from to cm−2 are obtained toward IRc7. The facts that the hot core emission peaks of vibrationally excited HC3N lines move from south to northeast with increasing , and that higher-energy HC3N lines have higher rotational temperatures and lower column densities, appear to support that the hot core is externally heated. The emission peaks are moving along the major axis of the SiO outflow, which may indicate that higher-energy HC3N transitions are excited by interaction between pre-existing dense medium and shocks generated by SiO outflows.

The Tibet experiment, operating at Yangbajing (4300 m above sea level), is the lowest energy air shower array, and the new high-density array constructed in 1996 is sensitive to gamma-ray air showers at energies as low as 3 TeV. With this new array, the Crab Nebula was observed in multi-TeV gamma-rays and a signal was detected at the 5.5 sigma level. We also obtained the energy spectrum of gamma-rays in the energy region above 3 TeV which partially overlaps those observed with imaging atmospheric Cerenkov telescopes. The Crab spectrum observed in this energy region can be represented by the power-law fit dJ&parl0;E&parr0;&solm0;dE=&parl0;4.61+/-0.90&parr0;x10-12&parl0;E&solm0;3 TeV&parr0;-2.62+/-0.17 cm-2 s-1 TeV-1. This is the first observation of gamma-ray signals from point sources with a conventional air shower array using scintillation detectors.

Carbon-bearing molecules, particularly CO, have been widely used as tracers of molecular gas in the interstellar medium (ISM). In this work, we aim to study the properties of molecules in diffuse, cold environments, where CO tends to be under-abundant and/or sub-thermally excited. We performed one of the most sensitive (down to τ CO rms ∼ 0.002 and τ HCO + rms ∼ 0.0008) sub-millimeter molecular absorption line observations towards 13 continuum sources with the ALMA. CO absorption was detected in diffuse ISM down to A v < 0.32 mag and HCO + was down to A v < 0.2 mag, where atomic gas and dark molecular gas (DMG) starts to dominate. Multiple transitions measured in absorption toward 3C454.3 allow for a direct determination of excitation temperatures T ex of 4.1 K and 2.7 K, for CO and for HCO + , respectively, which are close to the cosmic microwave background (CMB) and provide explanation for their being undercounted in emission surveys. A stronger linear correlation was found between N HCO + and N H2 (Pearson correlation coefficient P ∼ 0.93) than that of N CO and N H2 (P ∼ 0.33), suggesting HCO + being a better tracer of H 2 than CO in diffuse gas. The derived CO-to-H 2 conversion factor (the CO X-factor) of (14 ± 3) × 10 20 cm −2 (K km s −1 ) −1 is approximately 6 times larger than the average value found in the Milky Way.