122 research outputs found
Performance of AC-LGAD strip sensor designed for the DarkSHINE experiment
AC-coupled Low Gain Avalanche Detector (AC-LGAD) is a new precise detector
technology developed in recent years. Based on the standard Low Gain Avalanche
Detector (LGAD) technology, AC-LGAD sensors can provide excellent timing
performance and spatial resolution. This paper presents the design and
performance of several prototype AC-LGAD strip sensors for the DarkSHINE
tracking system, as well as the electrical characteristics and spatial
resolution of the prototype sensors from two batches of wafers with different
dose.The range of spatial resolutions of 6.5
8.2 and 8.8 12.3 are
achieved by the AC-LGAD sensors with 100 pitch size.Comment: 10 pages, 12 figure
The variation changes of the precipitation – runoff relationship
The variation of the rainfall-runoff relationship t will lead to the disappearance of the consistency assumption of engineering hydrology, which will influence the planning, design, operation management and development and utilization of water resources. Therefore, the variation diagnosis of the rainfall -runoff relationship has become one of the hot topics and key issues in this area. In this study, the variation points of the precipitation-runoff relationship are defined, the difference between the variation point and the mutation point is distinguished, and the method of variation classification is proposed based on the the dimensionless mean and variation coefficients. Then, a comprehensive diagnosis system of the rainfall-runoff relationship variation is constructed on the basis of systematically summarying and analyzing of the diagnosis method of rainfall - runoff relationship variation at home and abroad. Taking the Weihe River Basin as a case study, the comprehensive diagnosis system is verified by applying it to test the change point the annual runoff time series at the Huaxian hydrological station. And the results show that the comprehensive diagnosis method proposed in this paper is scientific and reasonable
The performance of large-pitch AC-LGAD with different N+ dose
AC-Coupled LGAD (AC-LGAD) is a new 4D detector developed based on the Low
Gain Avalanche Diode (LGAD) technology, which can accurately measure the time
and spatial information of particles. Institute of High Energy Physics (IHEP)
designed a large-size AC-LGAD with a pitch of 2000 {\mu}m and AC pad of 1000
{\mu}m, and explored the effect of N+ layer dose on the spatial resolution and
time resolution. The spatial resolution varied from 32.7 {\mu}m to 15.1 {\mu}m
depending on N+ dose. The time resolution does not change significantly at
different N+ doses, which is about 15-17 ps. AC-LGAD with a low N+ dose has a
large attenuation factor and better spatial resolution. Large signal
attenuation factor and low noise level are beneficial to improve the spatial
resolution of the AC-LGAD sensor
Application of metal-organic frameworks, covalent organic frameworks and their derivates for the metal-air batteries
Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) as the novel porous materials have the merits of diverse, adjustable functionality, high porosity and surface area, which have great application prospects in the gas storage, separation and catalysis. In addition, their derivates make up for the insufficient of electronic conductivity and chemical stability of MOFs and COFs, and provide a new ideal for accurate control of material structure. Up to now, many efficient electrocatalysts have been designed based on MOFs, COFs and their derivates for O2 reduction/evolution reactions (ORR/OER) and CO2 reduction/evolution reactions (CO2RR/CO2ER) in the metal-air batteries. In this review, the latest development of MOFs, COFs and their derivates in the metal-air batteries is summarized, and we discuss the structural characteristics of these materials and their corresponding mechanisms of action. By comprehensively reviewing the advantages, challenges and prospects of MOFs and COFs, we hope that the organic framework materials will shed more profound insights into the development of electrocatalysis and energy storage in the future
Characterization of the response of IHEP-IME LGAD with shallow carbon to Gamma Irradiation
Low Gain Avalanche Detectors (LGAD), as part of High-Granularity Timing
Detector (HGTD), is crucial to reducing pileup in the upgrading to HL-LHC. Many
studies have been done on the bulk damages of the LGAD. However, there's no
study about the surface radiation hardness of the LGAD sensors with carbon
implanted. The IHEP-IME LGAD version 3 with the shallow carbon and different
interpad separations were irradiated up to 2 MGy by gamma irradiation. The
performance of the IHEP-IME LGAD version 3 before and after irradiation had
been tested, such as the leakage current, break-down voltage, capacitance,
V, and inter-pad resistance. The results showed that apart from minor
fluctuations in some samples, no significant changes concerning inter-pad
separation were observed before and after irradiation. Leakage current and
break-down voltage increase after irradiation, which is considered due to
surface passivation; the overall inter-pad resistance are larger than $10^9\
\Omega_{gl}$ after irradiation. All parameters meet the
requirements of HGTD, and the results indicated that IHEP-IME LGAD v3 has
excellent anti-irradiation performance
Characterisation of Spatial and Timing Resolution of IHEP AC-LGAD Strip
AC-coupled LGAD(AC-LGAD) Strip is a new design of LGAD that allows
high-precision detection of particle spatiotemporal information whereas
reducing the density of readout electronics. For AC-LGAD Strips, there is
limited research on the impact of different strip pitches on the spatiotemporal
detection performance at the small amount of injected charge. The Institute of
High Energy Physics has designed an AC-LGAD Strip prototype with pitches of 150
, 200 , and 250 . The spatial and timing resolutions of
the prototype are studied through the laser Transient Current Technique (TCT)
scan with different amounts of injected charge. The results show that both the
spatial and timing resolution improves as the strip pitch decreases. Increases
in both temporal and spatial resolutions as the amount of charge injected
increases are observed. The spatial and timing resolution is better than 60 ps
and 40 at 1 Minimum Ionizing Particle (MIP), and better than 10 ps and
5 at 40 MIPs. Increasing Signal-to-Noise Ratio (SNR) is the key to
improving spatial and temporal resolution, whereas increasing the signal
attenuation rate by reducing the gap between adjacent electrodes also helps to
improve spatial resolution. The enhancements of spatial and timing resolutions
by both SNR and signal attenuation rate decrease with increasing amount of MIP.
This study can help design and optimize the AC-LGAD Strip detectors and readout
electronics
Functional interplay between SA1 and TRF1 in telomeric DNA binding and DNA-DNA pairing
Proper chromosome alignment and segregation during mitosis depend on cohesion between sister chromatids. Cohesion is thought to occur through the entrapment of DNA within the tripartite ring (Smc1, Smc3 and Rad21) with enforcement from a fourth subunit (SA1/SA2). Surprisingly, cohesin rings do not play a major role in sister telomere cohesion. Instead, this role is replaced by SA1 and telomere binding proteins (TRF1 and TIN2). Neither the DNA binding property of SA1 nor this unique telomere cohesion mechanism is understood. Here, using single-molecule fluorescence imaging, we discover that SA1 displays two-state binding on DNA: searching by one-dimensional (1D) free diffusion versus recognition through subdiffusive sliding at telomeric regions. The AT-hook motif in SA1 plays dual roles in modulating non-specific DNA binding and subdiffusive dynamics over telomeric regions. TRF1 tethers SA1 within telomeric regions that SA1 transiently interacts with. SA1 and TRF1 together form longer DNA-DNA pairing tracts than with TRF1 alone, as revealed by atomic force microscopy imaging. These results suggest that at telomeres cohesion relies on the molecular interplay between TRF1 and SA1 to promote DNA-DNA pairing, while along chromosomal arms the core cohesin assembly might also depend on SA1 1D diffusion on DNA and sequence-specific DNA binding
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