搜索结果: 1-15 共查到“理学 Positron”相关记录25条 . 查询时间(0.125 秒)
Heat Load and Stress Studies for an Design of the Photon Collimator for the ILC Positron Source
ILC collimator material stress high power beam absorption heat loads
2012/2/28
The ILC baseline design for the positron source is based on radiation from a helical undulator to produce positrons in a thin target. Since the photon beam created in the helical undulator is circular...
Angular distribution of Bremsstrahlung photons and of positrons for calculations of terrestrial gamma-ray flashes and positron beams
Bremsstrahlung pair production analytical integration of Bethe-Heitler equation distribution of scattering angles
2012/2/28
Within thunderstorms electrons can gain energies of up to hundred(s) of MeV. These electrons can create X-rays and gamma-rays as Bremsstrahlung when they collide with air molecules. Here we calculate ...
Positron attachment to the He doubly excited states
Positron attachment the He doubly excited states
2012/2/28
The projection method is used to demonstrate the existence of positron attachment to three doubly excited states of helium. The e+He(2s2 1Se), e+He(3s2 1Se), and the e+He(2s2p 3Po) states have binding...
Positron annihilation in the MuPs system
Positron annihilation the MuPs system Atomic Physics
2011/8/17
Abstract: The life-time of the four-body atomic system MuPs ($\mu^{+} e^{-}_2 e^{+}$ or muonium-positronium) against positron annihilation has been evaluated as $\tau = \frac{1}{\Gamma} \approx 4.0763...
Comment on "Interaction of two solitary waves in quantum electron-positron-ion plasma" [Phys. Plasmas \textbf{18}, 052301 (2011)]
two solitary waves quantum electron-positron-ion plasma
2011/8/4
Abstract: Recently, Yan-Xia Xu, et al. in the article Ref. [Phys. Plasmas \textbf{18}, 052301 (2011)] have studied the effects of various plasma parameters on interaction of two ion-acoustic solitary ...
In 2010 we celebrate 50 years since commissioning of the first particle storage ring ADA in Frascati (Italy) that also became the first electron-positron collider in 1964. After that date the particle...
Laser field absorption in self-generated electron-positron pair plasma
Laser field self-generated electron-positron pair plasma
2010/11/17
Recently much attention has being attracted to the problem of limitations on the attainable intensity of high power lasers [A.M. Fedotov {\it et al.} Phys. Rev. Lett. \textbf{105}, 080402 (2010)]. Th...
Cosmic ray propagation time scales: lessons from radioactive nuclei and positron data
High Energy Astrophysical Phenomena (astro-ph.HE) High Energy Physics - Phenomenology (hep-ph)
2011/1/4
We take a fresh look at high energy radioactive nuclei data reported in the 90's and at the positron data recently reported by PAMELA. Our aim is to study the model independent implications of these d...
Positron annihilation spectrum from the Galactic Centre region observed by SPI/INTEGRAL, revisited: annihilation in a cooling ISM?
High Energy Astrophysical Phenomena (astro-ph.HE)
2010/12/24
We analyse SPI/INTEGRAL data on the 511 keV line from the Galactic Centre, accumulated over ~6 years of observations.
Strong coupling，charm- and bottom-quark masses from electron-positron annihilation
strong coupling quark masses
2010/5/7
The cross section for electron-positron annihilation into hadrons allows for a precise determination of the strong coupling constant and the charm- and bottom-quark masses. Recent theoretical and expe...
Variational Calculation of Low-energy Positron Life Time in Xe Atoms
Positron Annihilation Bound wavefunction Scattered wavefunction Variational Method
2010/6/30
The least-squares variational method (LSVM) is used for determining trial wavefunctions representing lowenergy positron-xenon elastic scattering, which are used to determine the positron lifetime. The...
An advanced fully 3D OSEM reconstruction for positron emission tomography
3D OSEM PET symmetries sparse matrix
2010/5/7
A fully 3D OSEM reconstruction method for positron emission tomography (PET) based on symmetries and sparse matrix technique is described. Great savings in both storage space and computation time were...
Identification of pore size in porous SiO2 thin film by positron annihilation
Al-Si thin film porous SiO2 thin film positron annihilation
2009/8/14
Positron annihilation lifetime and Doppler broadening of annihilation line techniques have been used to obtain information about the small pore structure and size of porous SiO2 thin film produced by ...
Positronium annihilation in silica aerogel studied by a positron age-momentum correlation technique
positron age-momentum correlation positronium formation positron states silica aerogel
2009/8/14
A high-performance positron age-momentum correlation (AMOC) spectrometer was newly developed. The counting rate is increased up to 200 cps much larger than the value 20~cps reported by other internati...
Study of the background in the experiments of inner-shell ionization of atoms by positron impact
positron atomic ionization by positron impact Monte Carlo simulation
2009/8/14
One of main difficulties in the experiments of inner-shell ionization of atoms by positron impact near threshold energy region is the relatively high low-energy background, which is caused by the depo...