Searcharxiv⌕ Search

arXiv subjects

Qing Luo

Publications and source records attributed to Qing Luo.

26 records · Page 2Linked to original sources

Statistically study the optimal local sources for cosmic ray nuclei and electron

The local sources, such as Geminga SNR, may play important role for the anomaly of proton, electron and anisotropy in the past works. In fact, there exists twelve SNRs around solar system within $1$ kpc. One question is that can other SNRs also possibly contribute the spectra of nuclei and electron and explain the special structure of anisotropy? In this work, under the spatial-dependent propagation, we systematically study the contribution of all local SNRs within 1 kpc around solar to the spectra of nuclei and electron, as well as the energy dependence of anisotropy. As a result, only Geminga, Monogem, and Vela SNRs have quantitive contribution to the nuclei and electron spectra and anisotropy. Here, Geminga SNR is the sole optimal candidate and Monogem SNR is controversial due to the tension of anisotropy between model calculation and observations. The Vela SNR contributes a new spectral structure beyond TeV energy, hinted by HESS, VERITAS, DAMPE and CALET measurements. More interesting is that the electron anisotropy satisfies the Fermi-LAT limit below TeV energy, but rises greatly and reaches $10\%$ at several TeV. This new structure will shed new light to check our model. We hope that the new structure of electron spectrum and anisotropy can be observed by space-borne DAMPE and HERD and ground-based HAWC and LHAASO experiments in the near future.

astro-ph.HE↗

Multi-UAV Coverage Planning with Limited Endurance in Disaster Environment

For scenes such as floods and earthquakes, the disaster area is large, and rescue time is tight. Multi-UAV exploration is more efficient than a single UAV. Existing UAV exploration work is modeled as a Coverage Path Planning (CPP) task to achieve full coverage of the area in the presence of obstacles. However, the endurance capability of UAV is limited, and the rescue time is urgent. Thus, even using multiple UAVs cannot achieve complete disaster area coverage in time. Therefore, in this paper we propose a multi-Agent Endurance-limited CPP (MAEl-CPP) problem based on a priori heatmap of the disaster area, which requires the exploration of more valuable areas under limited energy. Furthermore, we propose a path planning algorithm for the MAEl-CPP problem, by ranking the possible disaster areas according to their importance through satellite or remote aerial images and completing path planning according to the importance level. Experimental results show that our proposed algorithm is at least twice as effective as the existing method in terms of search efficiency.

cs.RO↗

Quantum random number generator based on room-temperature single-photon emitter in gallium nitride

We experimentally demonstrate a real-time quantum random number generator by using a room-temperature single-photon emitter from the defect in a commercial gallium nitride wafer. Thanks to the brightness of our single photon emitter, the raw bit generation rate is ~1.8 MHz, and the unbiased bit generation rate is ~420 kHz after von Neumann's randomness extraction procedure. Our results show that commercial gallium nitride wafer has great potential for the development of integrated high-speed quantum random number generator devices.

quant-ph↗

The bunch current measurement using high-speed photodetector at HLS II

This contribution presents a novel bunch current measurement system based on an ultra-fast photodetector and a high-speed digitizer at Hefei Light Source II (HLS II). In order to achieve bunch-by-bunch resolution, the sampling rate of the system is nearly 225 GS/s via a dedicated equivalent sampling algorithm. According to preliminary tests of daily operation mode and single-bunch mode, the root-mean-square (rms) of current relative error distribution is 1.03%, which illustrates the new system satisfies requirements for high-precision bunch current measurement. In addition, experiment results of "HLS" Morse code fill pattern mode demonstrate this system also could be a convenient and robust tool for beam top-up mode in the future.

physics.acc-ph↗

Design and Simulation of a high order mode cavity bunch length monitor

A new bunch length measurement method based on high order mode cavity was proposed. Operating the harmonic cavity at mode TM0n0 so that its radius could be chosen, in order to break the limitation of beam pipe radius. A two-cavity bunch length monitor for linac of positron source was designed. Operating frequency selection for different bunch time structure was discussed and calculation formula of bunch length was deducted. Fundamental harmonic cavity resonates at 2.856 GHz with mode TM010. Fifth harmonic cavity resonates at 14.28 GHz (fifth harmonic of the linac fundamental frequency 2.856 GHz) with mode TM020, which could provide larger radius. Each cavity equipped with a filter to suppress unwanted signal. A simulation measurement was conducted in CST Particle Studio for beam current from 100-300mA, bunch length from 5-10ps, calculation results shows a fairly high accuracy (better than 3%). Several cases were discussed.

physics.acc-ph↗

Beam size and position measurement based on logarithm processing algorithm in HLS II

A logarithm processing algorithm to measure beam transverse size and position is proposed and preliminary experimental results in Hefei Light Source II (HLS II) are given. The algorithm is based on only 4 successive channels of 16 anode channels of multianode photomultiplier tube (MAPMT) R5900U-00-L16 which has typical rise time of 0.6 ns and effective area of 0.8x16 mm for a single anode channel. In the paper, we firstly elaborate the simulation results of the algorithm with and without channel inconsistency. Then we calibrate the channel inconsistency and verify the algorithm using general current signal processor Libera Photon in low-speed scheme. Finally we get turn-by-turn beam size and position and calculate the vertical tune in high-speed scheme. The experimental results show that measured values fit well with simulation results after channel differences are calibrated and the fractional part of the tune in vertical direction is 0.3628 which is very close to the nominal value 0.3621.

physics.acc-ph↗

Concept for a Future Super Proton-Proton Collider

Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.

physics.acc-ph↗