7 research outputs found
Calibration of photomultiplier using UVLED
Detector calibration is very important for the long-term operation. For the
purposes of simple and precise calibration, we developed a new portable
calibration source using UVLED to calibrate the fluorescence detector of the
Telescope Array experiment (TA). The UVLED is light (less than 1 kg) and its
setup is quick and easy. Therefore, a single source will be used instead of the
calibration sources that TA currently uses. The UVLED emits 369 nm wavelength
and ~70 pJ of photons which are calibrated with 5% accuracy us-ing photo-diode.
It has a particular unit, which is an internal heater, to keep the temperature
constant and avoiding temperature dependency on light yield. The first result
of calibration for 24 detectors is xx pho-tons/faced count for 369 nm photons
with 6% uncertainty. It is in agreement with the result of the current
calibration sources of TA
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
Measurement of the branching fractions for Cabibbo-suppressed decays and at Belle
International audienceWe present measurements of the branching fractions for the singly Cabibbo-suppressed decays and , and the doubly Cabibbo-suppressed decay , based on 980 of data recorded by the Belle experiment at the KEKB collider. We measure these modes relative to the Cabibbo-favored modes and . Our results for the ratios of branching fractions are , , and , where the uncertainties are statistical and systematic, respectively. The second value corresponds to , where is the Cabibbo angle; this value is larger than other measured ratios of branching fractions for a doubly Cabibbo-suppressed charm decay to a Cabibbo-favored decay. Multiplying these results by world average values for and yields , , and , where the third uncertainty is due to the branching fraction of the normalization mode. The first two results are consistent with, but more precise than, the current world averages. The last result is the first measurement of this branching fraction
Measurement of the production ratio in collisions at the resonance using decays at Belle
We measure the ratio of branching fractions for the decays to and using and samples, where stands for ( or ), with fb of data collected at the resonance with the Belle detector. We find the decay rate ratio of over to be , which is the most precise measurement to date. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainty is systematic due to the assumption of isospin symmetry in
Measurement of branching fractions of and at Belle
We present a study of a singly Cabibbo-suppressed decay and a Cabibbo-favored decay based on 980 of data collected by the Belle detector, operating at the KEKB energy-asymmetric collider. We measure their branching fractions relative to : and . Combining with the world average , we have the absolute branching fractions: and . The first and second uncertainties are statistical and systematic, respectively, while the third ones arise from the uncertainty on . The mode is observed for the first time and has a statistical significance of . The branching fraction of has been measured with a threefold improvement in precision over previous results and is found to be consistent with the world average
Test of light-lepton universality in decays with the Belle II experiment
International audienceWe present a measurement of the ratio of branching fractions of the lepton decaying to muons or electrons using data collected with the Belle II detector at the SuperKEKB collider. The sample has an integrated luminosity of 362 fb at a centre-of-mass energy of 10.58 GeV. Using an optimised event selection, a binned maximum likelihood fit is performed using the momentum spectra of the electron and muon candidates. The result, , where the first uncertainty is statistical and the second is systematic, is the most precise to date. It provides a stringent test of the light-lepton universality, translating to a ratio of the couplings of the muon and electron to the boson in decays of , in agreement with the standard model expectation of unity