Beam-energy and collision-system dependence of the linear and mode-coupled flow harmonics from STAR

We calculated the hypertriton production at RHIC-STAR and HIRFL-CSR acceptance, with a multi-phase transport model (AMPT) and a relativistic transport model (ART), respectively. In specific, we calculated the Strangeness Population Factor [Formula: see text] at different beam energy. Our results from AGS to RHIC energy indicated that the collision system may change from hadronic phase at AGS energies to partonic phase at RHIC energies. Our calculation at HIRFL-CSR energy supports the proposal to measure hypertriton at HIRFL-CSR.

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Collision system and beam energy dependence of anisotropic flow fluctuations

Nuclear Physics A ◽

10.1016/j.nuclphysa.2018.09.027 ◽

2019 ◽

Vol 982 ◽

pp. 255-258 ◽

Cited By ~ 3

Author(s):

Niseem Magdy

Keyword(s):

Energy Dependence ◽

Beam Energy ◽

Collision System ◽

Anisotropic Flow ◽

Flow Fluctuations

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Beam energy and system dependence of rapidity-even dipolar flow

EPJ Web of Conferences ◽

10.1051/epjconf/201817116002 ◽

2018 ◽

Vol 171 ◽

pp. 16002

Author(s):

Niseem Magdy

Keyword(s):

Beam Energy ◽

Collision System ◽

Initial State ◽

Specific Viscosity ◽

200 Gev

New measurements of rapidity-even dipolar flow, veven1, are presented for several transverse momenta, pT, and centrality intervals in Au+Au collisions at [see formula in PDF] = 200, 39 and 19.6 GeV, U+U collisions at [see formula in PDF] = 193 GeV, and Cu+Au, Cu+Cu, d+Au and p+Au collisions at [see formula in PDF] = 200 GeV. The veven1 shows characteristic dependencies on pT, centrality, collision system and [see formula in PDF], consistent with the expectation from a hydrodynamic-like expansion to the dipolar fluctuation in the initial state. These measurements could serve as constraints to distinguish between different initialstate models, and aid a more reliable extraction of the specific viscosity η/s.

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Edge Penetration Effects in the Low-Loss Electron Image in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103097 ◽

1988 ◽

Vol 46 ◽

pp. 202-203

Author(s):

Oliver C. Wells

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Beam Energy ◽

Secondary Electron ◽

Sharp Edge ◽

Beam Diameter ◽

Low Loss ◽

Additional Information ◽

Electron Image ◽

Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.

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Electron beam induced current study of thin silicon layers on insulator substrate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176228 ◽

1990 ◽

Vol 48 (4) ◽

pp. 618-619

Author(s):

A. Buczkowski ◽

Z. J. Radzimski ◽

J. C. Russ ◽

G. A. Rozgonyi

Keyword(s):

Electron Beam ◽

Energy Loss ◽

Beam Energy ◽

Collection Efficiency ◽

Silicon Layer ◽

Depletion Layer ◽

Incident Electron Energy ◽

Induced Current ◽

Electron Hole ◽

Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

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Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017685x ◽

1990 ◽

Vol 48 (4) ◽

pp. 744-745

Author(s):

D.P. Malta ◽

M.L. Timmons

Keyword(s):

Electron Beam ◽

Beam Energy ◽

Minority Carrier ◽

Diffusion Length ◽

Effective Diffusion ◽

Surface Recombination ◽

Surface Recombination Velocity ◽

Logarithmic Scale ◽

Minority Carrier Diffusion Length ◽

Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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