878 research outputs found
Measurement and Compensation of Horizontal Crabbing at the Cornell Electron Storage Ring Test Accelerator
In storage rings, horizontal dispersion in the rf cavities introduces
horizontal-longitudinal (xz) coupling, contributing to beam tilt in the xz
plane. This coupling can be characterized by a "crabbing" dispersion term
{\zeta}a that appears in the normal mode decomposition of the 1-turn transfer
matrix. {\zeta}a is proportional to the rf cavity voltage and the horizontal
dispersion in the cavity. We report experiments at the Cornell Electron Storage
Ring Test Accelerator (CesrTA) where xz coupling was explored using three
lattices with distinct crabbing properties. We characterize the xz coupling for
each case by measuring the horizontal projection of the beam with a beam size
monitor. The three lattice configurations correspond to a) 16 mrad xz tilt at
the beam size monitor source point, b) compensation of the {\zeta}a introduced
by one of two pairs of RF cavities with the second, and c) zero dispersion in
RF cavities, eliminating {\zeta}a entirely. Additionally, intrabeam scattering
(IBS) is evident in our measurements of beam size vs. rf voltage.Comment: 5 figures, 10 page
Central limit theorems for the real eigenvalues of large Gaussian random matrices
Let G be an N×N real matrix whose entries are independent identically distributed standard normal random variables Gij∼N(0,1). The eigenvalues of such matrices are known to form a two-component system consisting of purely real and complex conjugated points. The purpose of this paper is to show that by appropriately adapting the methods of [E. Kanzieper, M. Poplavskyi, C. Timm, R. Tribe and O. Zaboronski, Annals of Applied Probability 26(5) (2016) 2733–2753], we can prove a central limit theorem of the following form: if λ1,…,λNR are the real eigenvalues of G, then for any even polynomial function P(x) and even N=2n, we have the convergence in distribution to a normal random variable
1E(NR)−−−−−√⎛⎝∑j=1NRP(λj/2n−−√)−E∑j=1NRP(λj/2n−−√)⎞⎠→N(0,σ2(P))
as n→∞, where σ2(P)=2−2√2∫1−1P(x)2dx
Accelerator Design for the CHESS-U Upgrade
During the summer and fall of 2018 the Cornell High Energy Synchrotron Source
(CHESS) is undergoing an upgrade to increase high-energy flux for x-ray users.
The upgrade requires replacing one-sixth of the Cornell Electron Storage Ring
(CESR), inverting the polarity of half of the CHESS beam lines, and switching
to single-beam on-axis operation. The new sextant is comprised of six
double-bend achromats (DBAs) with combined-function dipole-quadrupoles.
Although the DBA design is widely utilized and well understood, the constraints
for the CESR modifications make the CHESS-U lattice unique. This paper
describes the design objectives, constraints, and implementation for the CESR
accelerator upgrade for CHESS-U
The Partition Function of Multicomponent Log-Gases
We give an expression for the partition function of a one-dimensional log-gas
comprised of particles of (possibly) different integer charge at inverse
temperature {\beta} = 1 (restricted to the line in the presence of a
neutralizing field) in terms of the Berezin integral of an associated non-
homogeneous alternating tensor. This is the analog of the de Bruijn integral
identities [3] (for {\beta} = 1 and {\beta} = 4) ensembles extended to
multicomponent ensembles.Comment: 14 page
Detecting specific oscillatory regimes in the dynamics of erbium-doped fiber laser
A method for determining the oscillatory mode occurring in an erbiumdoped fiber laser with a modulated parameter is proposed. The method is based on using a continuous wavelet transform with a mother Morlet wavelet and analyzing the energy of the wavelet spectrum that corresponds to the relevant range of time scales
Intrabeam Scattering Studies at CesrTA
Intrabeam scattering (IBS) limits the emittance and single-bunch current that
can be achieved in electron or positron storage ring colliders, damping rings,
and light sources. Much theoretical work on IBS exists, and while the theories
have been validated in hadron and ion machines, the presence of strong damping
makes IBS in lepton machines a different phenomenon. We present the results of
measurements at CesrTA of IBS dominated beams, and compare the data with
theory. The beams we study have parameters typical of those specified for the
next generation of wiggler dominated storage rings: low emittance, small bunch
length, and few GeV energy. Our measurements are in good agreement with IBS
theory, provided a tail-cut procedure is applied.Comment: 14 pages, 15 figure
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