The High Energy Photon Source (HEPS), a kilometer-scale storage ring light source with the energy of 6GeV is to be built in China. For the injection scheme of the storage ring, on-axis injection is the baseline scheme...
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The High Energy Photon Source (HEPS) is a fourth-generation light source with a beam energy of 6 GeV currently under development by the Institute of High Energy physics. The Beam Loss Monitor (BLM) system is designed ...
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Introduction The circular electron-positron collider(CEPC)will use a 650-MHz RF system with 240 two-cell cavities for the *** collider is a double ring with shared cavities for Higgs operation and separate cavities fo...
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Introduction The circular electron-positron collider(CEPC)will use a 650-MHz RF system with 240 two-cell cavities for the *** collider is a double ring with shared cavities for Higgs operation and separate cavities for W and Z *** higher-order modes(HOM)excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch *** and methods To get the real damping results,two prototypes of HOM coupler have been fabricated and installed on the 650-MHz two-cell *** HOMs have been verified by bead pulling method.A test bench with two 2-cell cavities is used to measure the real damping results and study HOM propagating properties for a cavity *** In this paper,the impedance budget,HOM damping and HOM power requirements for the CEPC collider ring are *** damping results measured for the fundamental mode and HOMs seem good compared with the simulated *** absorbing efficiency of the absorber and the extraction power efficiency of HOM couplers were also achieved.
The observed spectral bump around 10 TV in cosmic-ray (CR) proton and helium spectra, along with the phase and amplitude evolution of CR dipole anisotropy, provide plausible yet indirect evidence for the presence of a...
The observed spectral bump around 10 TV in cosmic-ray (CR) proton and helium spectra, along with the phase and amplitude evolution of CR dipole anisotropy, provide plausible yet indirect evidence for the presence of a nearby CR source. This study investigates the potential of giant molecular clouds (GMCs) located near the solar system to act as natural probes of CRs from the nearby source, with their gamma-ray emissions serving as indicators of spatial variations in CR flux within the solar neighborhood resulting from this source. We show that a nearby source, accounting for the CR data, could imprint distinct features on the γ-ray spectra of different GMCs. We expect that these features are detectable by the Large High Altitude Air Shower Observatory and upcoming high-energy γ-ray observatories, providing a powerful test for the hypothesized nearby source. Notably, we find that determining the energy dependence of the γ-ray spectral index offers a promising approach to investigate the nearby source and constrain its distance. Conversely, if the spectral bump is a widespread Galactic phenomenon, the energy dependence would exhibit uniformity across all GMCs, distinguishing the underlying mechanism accounting for the spectral bump from the scenario involving a nearby source.
Purpose Circular Electron Positron Collider(CEPC)is a 100-km-ring e+e−collider for a Higgs *** injector is composed of a 10-GeV Linac and a 120-GeV *** CEPC Linac is a normal conducting S-band Linac with frequency of ...
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Purpose Circular Electron Positron Collider(CEPC)is a 100-km-ring e+e−collider for a Higgs *** injector is composed of a 10-GeV Linac and a 120-GeV *** CEPC Linac is a normal conducting S-band Linac with frequency of 2860 MHz providing electron and positron beams at an energy up to 10 GeV with 100 Hz repetition *** positron source is the most important part of the CEPC Linac,and the bunch charge of positron beam within some cut-off condition should be larger than 3 *** The positron source of CEPC is composed of a target,a flux concentrator,a capture section,a pre-accelerating section and a beam separation *** positron yield and capture efficiency are the design *** on simulation,the design will be presented and discussed in *** The positron yield at the PSPAS exit is larger than 0.55,and the normalized rms emittance is 2370 mm-mrad with a strict cut-off *** detailed simulation results will be *** The design of the positron source including positron production and capture will be presented and can meet the requirements.
The large array of imaging atmospheric Cherenkov telescopes（LACT） is a planned array of 32 Cherenkov telescopes,each featuring 6-m diameter mirrors,to be constructed at the LHAASO *** study focused on optimizing the...
The large array of imaging atmospheric Cherenkov telescopes（LACT） is a planned array of 32 Cherenkov telescopes,each featuring 6-m diameter mirrors,to be constructed at the LHAASO *** study focused on optimizing the array layout and analyzing the performance of *** observation modes were examined:large zenith angle observations for ultra-high energy events and small zenith angle observations for lower energy *** large zenith angles（60°）,simulations indicate that an 8-telescope subarray can achieve an effective area of 3 km2with excellent angular *** small zenith angles,we optimized the layout of 4-telescope cells and the full 32-telescope *** energy threshold of the full array is approximately 200 GeV,which is particularly crucial for studying transient phenomena such as gamma-ray bursts（GRBs） and active galactic nuclei（AGNs）.This study provides essential guidance for finalizing the LACT layout design and estimating performance under various observational *** also highlights the potential of LACT for conducting deep observations of ultrahigh energy γ-ray sources,performing morphological studies of PeVatrons,and advancing time-domain γ-ray astrono my.
X-band accelerators for multi-bunches are a new way to produce high luminosity and energy efficiency bunches. The smaller the size and the more bunches, the more severe is the wakefield in the X-band accelerators, unl...
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X-band accelerators for multi-bunches are a new way to produce high luminosity and energy efficiency bunches. The smaller the size and the more bunches, the more severe is the wakefield in the X-band accelerators, unless some means of strongly suppressing the transverse wakefield is adopted in the design of the accelerating structure. Here, the derivation of the wakefield function of the double circuit model and its application to the designed accelerator structure have been demonstrated.
Circular Electron-Positron Collider (CEPC) is a 100 km ring collider as a Higgs factory. It consists of a double ring collider, a full energy booster, a Linac and several transport lines. The Linac is a normal conduct...
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The High Energy Photon Source is a 6-GeV, kilometre-scale storage ring light source to be built in Beijing. A lattice of the storage ring was proposed, consisting of 48 hybrid 7BAs, and having a natural emittance of 6...
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The High Energy Photon Source (HEPS) is the next ring-based light source to be built in China, with an emit-tance of tens of picometers, and a circumference of about 1.3 km. After 10 years' evolution, the design f...
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