2,791 research outputs found
Effect of the superconducting wiggler on the DELSY beam dynamics
The project DELSY is being under development at JINR, Dubna, Russia. This
synchrotron radiation source is dedicated to the investigation on condensed
matter physics, atomic physics, biology, medicine, chemistry, micromechanics,
lithography and others. The storage ring DELSY is an electron storage ring with
the beam energy 1.2 GeV and 4 straight sections to accommodate accelerator
equipment and insertion devices. One of the straight sections is intended for a
10 T superconducting wiggler (wavelength shifter) and one for the undulator
with 150 periods and a magnetic field of 0.75 T. The wiggler will influence
many aspects of beam dynamics: linear motion, dynamic aperture, emittance,
damping times etc. The problem is rather serious for the DELSY machine because
the energy of the electron beam is small while the wiggler's magnetic field is
strong. In this paper we consider two models of the wiggler's magnetic field
with and without the focusing caused by the sextupolar field of the wiggler as
we need to develop the requirements to the wiggler design. We study the
influence of the 10 T wiggler on the beam dynamics in the DELSY storage ring
and propose a possible scheme to cure it. The combined work of the insertion
device is presented too.Comment: 17 pages, submitted to journal NIM
Energy transfer in binary collisions of two gyrating charged particles in a magnetic field
Binary collisions of the gyrating charged particles in an external magnetic
field are considered within a classical second-order perturbation theory, i.e.,
up to contributions which are quadratic in the binary interaction, starting
from the unperturbed helical motion of the particles. The calculations are done
with the help of a binary collisions treatment which is valid for any strength
of the magnetic field and involves all harmonics of the particles cyclotron
motion. The energy transfer is explicitly calculated for a regularized and
screened potential which is both of finite range and nonsingular at the origin.
The validity of the perturbation treatment is evaluated by comparing with
classical trajectory Monte Carlo (CTMC) calculations which also allow to
investigate the strong collisions with large energy and velocity transfer at
low velocities. For large initial velocities on the other hand, only small
velocity transfers occur. There the nonperturbative numerical CTMC results
agree excellently with the predictions of the perturbative treatment.Comment: 12 pages, 4 figure
Nonlocal symmetries of integrable two-field divergent evolutionary systems
Nonlocal symmetries for exactly integrable two-field evolutionary systems of
the third order have been computed. Differentiation of the nonlocal symmetries
with respect to spatial variable gives a few nonevolutionary systems for each
evolutionary system. Zero curvature representations for some new nonevolution
systems are presented
Suspensions Thermal Noise in the LIGO Gravitational Wave Detector
We present a calculation of the maximum sensitivity achievable by the LIGO
Gravitational wave detector in construction, due to limiting thermal noise of
its suspensions. We present a method to calculate thermal noise that allows the
prediction of the suspension thermal noise in all its 6 degrees of freedom,
from the energy dissipation due to the elasticity of the suspension wires. We
show how this approach encompasses and explains previous ways to approximate
the thermal noise limit in gravitational waver detectors. We show how this
approach can be extended to more complicated suspensions to be used in future
LIGO detectors.Comment: 28 pages, 13 figure
Production of para-- and orthopositronium at relativistic heavy ion colliders
We consider the ortho-- and parapositronium production in the process Ps where A is a nucleus with the charge number Z. The inclusive cross
section and the energy distribution of the relativistic Ps are calculated which
are of primary interest from the experimental point of view. The accuracy of
the corresponding cross sections is given by omitting terms for the para--Ps and for the ortho--Ps production
where and 16 for the RHIC and the LHC. Within this
accuracy the multiphoton (Coulomb) corrections are taken into account. We show
that the RHIC and the LHC will be Ps factories with a productions rate of about
relativistic Ps per day. The fraction of the ortho--Ps is
expected to be of the same order as that of the para--Ps for Au--Au and Pb--Pb
collisions.Comment: 22 pages, 5 figures, RevTeX, misprint correcte
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