2,292 research outputs found
Non-invasive characterization of transverse beam emittance of electrons from a laser-plasma wakefield accelerator in the bubble regime using betatron x-ray radiation
We propose and use a technique to measure the transverse emittance of a
laser-wakefield accelerated beam of relativistic electrons. The technique is
based on the simultaneous measurements of the electron beam divergence given by
, the measured longitudinal spectrum
and the transverse electron bunch size in the bubble
. The latter is obtained via the measurement of the source size of
the x-rays emitted by the accelerating electron bunch in the bubble. We measure
a \textit{normalised} RMS beam transverse emittance mmmrad as
an upper limit for a spatially gaussian, spectrally quasi-monoenergetic
electron beam with 230 MeV energy in agreement with numerical modeling and
analytic theory in the bubble regime.Comment: 4 pages, 5 figure
Longitudinal Flow of Protons from 2-8 AGeV Central Au+Au Collisions
Rapidity distributions of protons from central Au + Au
collisions measured by the E895 Collaboration in the energy range from 2 to 8
AGeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived
using a thermal model including collective longitudinal expansion are extracted
from these distributions. The results show an approximately linear increase in
the longitudinal flow velocity, , as a function of the
logarithm of beam energy.Comment: 5 Pages, including 3 figures, 1 tabl
Laying the groundwork at the AGS: Recent results from experiment E895
The E895 Collaboration at the Brookhaven AGS has performed a systematic
investigation of Au+Au collisions at 2-8 AGeV, using a large-acceptance Time
Projection Chamber. In addition to extensive measurements of particle flow,
spectra, two-particle interferometry, and strangeness production, we have
performed novel hybrid analyses, including azimuthally-sensitive pion HBT,
extraction of the six-dimensional pion phasespace density, and a first
measurement of the Lambda-proton correlation function.Comment: Presented at Quark Matter 2001, 8 pages, 5 figure
Charged Pion Production in 2 to 8 AGeV Central Au+Au Collisions
Momentum spectra of charged pions over nearly full rapidity coverage from
target to beam rapidity have been measured in the 0-5% most central Au+Au
collisions in the beam energy range from 2 to 8 AGeV by the E895 Experiment.
Using a thermal parameterization to fit the transverse mass spectra, rapidity
density distributions are extracted. The observed spectra are compared with
predictions from the RQMD v2.3 cascade model and also to a thermal model
including longitudinal flow. The total 4 yields of the charged pions are
used to infer an initial state entropy produced in the collisions.Comment: 13 pgs, 19 figs, accepted by Phys. Rev. C. Data tables available at
http://nuclear.ucdavis.edu/~e895/published_spectra.htm
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