Yuan-Hann Chang
A5049010336- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Geomagnetism and Paleomagnetism Studies
- Gamma-ray bursts and supernovae
- Particle physics theoretical and experimental studies
- Radiation Therapy and Dosimetry
- Atomic and Subatomic Physics Research
- Ionosphere and magnetosphere dynamics
- Atmospheric Ozone and Climate
- Advanced MEMS and NEMS Technologies
- Astro and Planetary Science
- Neutrino Physics Research
- Superconducting Materials and Applications
- Radio Astronomy Observations and Technology
- Magnetic Field Sensors Techniques
- Advancements in Semiconductor Devices and Circuit Design
- Acoustic Wave Resonator Technologies
- Electrostatic Discharge in Electronics
- Particle accelerators and beam dynamics
- Computational Physics and Python Applications
- Employment and Welfare Studies
Institute of Physics, Academia Sinica
2021-2025
National Central University
2009-2022
National Chung Hsing University
2022
National Synchrotron Radiation Research Center
2022
Massachusetts Institute of Technology
2020
European Organization for Nuclear Research
2000
A precision measurement by the Alpha Magnetic Spectrometer on International Space Station of positron fraction in primary cosmic rays energy range from 0.5 to 350 GeV based $6.8\ifmmode\times\else\texttimes\fi{}{10}^{6}$ and electron events is presented. The very accurate data show that steadily increasing 10 $\ensuremath{\sim}250\text{ }\text{ }\mathrm{GeV}$, but, 20 250 GeV, slope decreases an order magnitude. spectrum shows no fine structure, ratio observable anisotropy. Together, these...
Measurements of the positron fraction in high energy cosmic rays using space-borne Alpha Magnetic Spectrometer have been extended to energies 500 GeV. The new results show that stops increasing with at around 200
Knowledge of the precise rigidity dependence helium flux is important in understanding origin, acceleration, and propagation cosmic rays. A measurement primary rays with (momentum/charge) from 1.9 GV to 3 TV based on 50 million events presented compared proton flux. The detailed variation spectral index for first time. progressively hardens at rigidities larger than 100 GV. similar that though magnitudes are different. Remarkably, ratio increases up 45 then becomes constant; above well...
The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station (ISS) conducting unique, long-duration mission of fundamental research in space. objectives include precise studies origin dark matter, antimatter, and cosmic rays as well exploration new phenomena. Following 16-year period construction testing, precursor flight Shuttle, AMS was installed ISS May 19, 2011. In this report we present results based 120 billion charged ray events up...
A measurement of the cosmic ray positron fraction e+/(e++e−) in energy range 1–30 GeV is presented. The based on data taken by AMS-01 experiment during its 10 day Space Shuttle flight June 1998. proton background suppression order 106 reached identifying converted bremsstrahlung photons emitted from positrons.
We report the observation of new properties primary cosmic rays He, C, and O measured in rigidity (momentum/charge) range 2 GV to 3 TV with 90×10^{6} helium, 8.4×10^{6} carbon, 7.0×10^{6} oxygen nuclei collected by Alpha Magnetic Spectrometer (AMS) during first five years operation. Above 60 GV, these three spectra have identical dependence. They all deviate from a single power law above 200 harden an way.
We present a measurement of the cosmic ray (e^{+}+e^{-}) flux in range 0.5 GeV to 1 TeV based on analysis 10.6 million events collected by AMS. The statistics and resolution AMS provide precision flux. is smooth reveals new distinct information. Above 30.2 GeV, can be described single power law with spectral index γ=-3.170±0.008(stat+syst)±0.008(energy scale).
Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million collected by the Alpha Magnetic Spectrometer International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties (a) a significant excess starting from 25.2±1.8 GeV compared lower-energy, power-law trend, (b) sharp dropoff above 284+91−64 GeV, (c) in entire range is well described sum term associated with produced collision rays, which dominates at low...
Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based $28.1\ifmmode\times\else\texttimes\fi{}{10}^{6}$ collected by Alpha Magnetic Spectrometer International Space Station. In entire electron and positron spectra have distinctly different magnitudes dependences. The flux exhibits a significant excess starting $42.{1}_{\ensuremath{-}5.2}^{+5.4}\text{ }\text{ }\mathrm{GeV}$ compared lower trends, but nature of this is above...
We present the precision measurement of daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total 2824 days or 114 Bartels rotations) rigidity interval 1 100 GV based on 5.5×10^{9} protons collected with Alpha Magnetic Spectrometer aboard International Space Station. The exhibit variations multiple timescales. From 2014 2018, we observed recurrent flux a period 27 days. Shorter periods 9 and 13.5 are 2016. strength all three periodicities changes time rigidity....
This Letter reports on the first results from Taiwan Axion Search Experiment with a Haloscope, search for axions using microwave cavity at frequencies between 4.707 50 and 4.798 15 GHz. Apart nonaxion signals, no candidates significance of more than 3.355 were found. The experiment excludes models axion-two-photon coupling $|{g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}|\ensuremath{\gtrsim}8.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}\text{ }\text{...
We report the properties of precision time structures cosmic nuclei He, Li, Be, B, C, N, and O fluxes over an 11-year solar cycle from May 2011 to November 2022 in rigidity range 1.92 60.3 GV. The show similar but not identical variations with amplitudes decreasing increasing rigidity. In particular, below 3.64 GV B fluxes, 2.15 are significantly less affected by modulation than He flux. observe that these differences linearly correlated spectral indices fluxes. This shows, a...
Precise knowledge of the charge and rigidity dependence secondary cosmic ray fluxes secondary-to-primary flux ratios is essential in understanding propagation. We report properties heavy fluorine F R range 2.15 GV to 2.9 TV based on 0.29 million events collected by Alpha Magnetic Spectrometer experiment International Space Station. The spectrum deviates from a single power law above 200 GV. heavier F/Si ratio distinctly different lighter B/O (or B/C) dependence. In particular, 10 GV, F/SiB/O...
Abstract Distributed computing frameworks play a crucial role in supporting compute-intensive applications the era of big data. The growing demand for resources has spurred interconnection data centers, leading to formation supercomputing Internet. MapReduce is popular distributed framework designed large independent clusters. original deployed on Internet performs inefficiently due redundant geo-distributed reduce operations. Nonetheless, its abstraction remains significant potential. This...
Measurement of the chemical and isotopic composition cosmic rays is essential for precise understanding their propagation in galaxy. While model parameters are mainly determined using B/C ratio, study extended sets ratios can provide stronger constraints on models. In this paper, relative abundances light-nuclei lithium, beryllium, boron, carbon presented. The secondary-to-primary Li/C, Be/C, have been measured kinetic energy range 0.35–45 GeV nucleon−1. ratio 7Li/6Li also magnetic rigidity...
The variety of isotopes in cosmic rays allows us to study different aspects the processes that undergo between time they are produced and their arrival heliosphere. In this paper, we present measurements isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be), 10B/11B range 0.2–1.4 GeV kinetic energy per nucleon. based on data collected by Alpha Magnetic Spectrometer, AMS-01, during STS-91 flight 1998 June.
Abstract The authors examine job stress and work attitudes among temporary (i.e. fixed‐term) permanently employed nurses, using data collected via a structured questionnaire filled out by 249 nurses in two hospitals northern Taiwan. Temporary the sample were generally younger, less experienced, unmarried, or married without children. Questionnaire responses also indicate that they suffer from greater lower affective organizational occupational commitments compared to their permanent...
We report on a holoscope axion search experiment near 19.6 µeV from the Taiwan Axion Search Experiment with Haloscope collaboration. This is carried out via frequency-tunable cavity detector volume V = 0.234 liter in magnetic field B0 8 T. With signal receiver that has system noise temperature Tsys ≅ 2.2 K and an time of about one month, excludes values axion–photon coupling constant gaγγ ≳ 8.1 × 10−14 GeV−1, factor 11 above Kim–Shifman–Vainshtein–Zakharov benchmark model, at 95% confidence...
The Nuclear Compton Telescope (NCT) is a balloon-borne telescope designed to study astrophysical sources of nuclear line emission and polarization at soft gamma-ray (0.2-10 MeV) energies. NCT uses high-purity germanium strip detectors for 3D tracking photon interactions. imaging enables effective background rejection, resulting in compact but highly efficient instrument. prototype completed successful flight from Fort Sumner, New Mexico 2005. We have since integrated additional detectors,...