297 research outputs found
High luminosity interaction region design for collisions inside high field detector solenoid
An innovatory interaction region has been recently conceived and realized on
the Frascati DA{\Phi}NE lepton collider. The concept of tight focusing and
small crossing angle adopted to achieve high luminosity in multibunch
collisions has evolved towards enhanced beam focusing at the interaction point
with large horizontal crossing angle, thanks to a new compensation mechanism
for the beam-beam resonances. The novel configuration has been tested with a
small detector without solenoidal field yielding a remarkable improvement in
terms of peak as well as integrated luminosity. The high luminosity interaction
region has now been modified to host a large detector with a strong solenoidal
field which significantly perturbs the beam optics introducing new design
challenges in terms of interaction region optics design, beam transverse
coupling control and beam stay clear requirements. Interaction region design
criteria as well as the luminosity results relevant to the structure test are
presented and discussed.Comment: 12 pages, 9 figures, submitted to JINS
Results from the DAΦNE high luminosity test
In the second half of 2007 the Frascati DAΦNE collider has been upgraded in order to test an innovative collision scheme based on large Piwinski angle and providing for Crab-Waist compensation of the beam-beam interaction. In the following the main upgrade motivations are explained and the achieved results are presented and discussed
High luminosity interaction region design for collisions with detector solenoid
An innovatory interaction region has been recently conceived and realized on
the Frascati DA{\Phi}NE lepton collider. The concept of tight focusing and
small crossing angle adopted until now to achieve high luminosity in multibunch
collisions has evolved towards enhanced beam focusing at the interaction point
with large horizontal crossing angle, thanks to a new compensation mechanism
for the beam-beam resonances. The novel configuration has been tested with a
small detector without solenoidal field yielding a remarkable improvement in
terms of peak as well as integrated luminosity. The high luminosity interaction
region has now been modified to host a large detector with a strong solenoidal
field which significantly perturbs the beam optics introducing new design
challenges in terms of interaction region optics design, beam transverse
coupling control and beam stay clear requirementsComment: 3 pages, 4 figures, presented to the IPAC10 conferenc
Synchrotron oscillation damping due to beam-beam collisions
In DA{\Phi}NE, the Frascati e+/e- collider, the crab waist collision scheme
has been successfully implemented in 2008 and 2009. During the collision
operations for Siddharta experiment, an unusual synchrotron damping effect has
been observed. Indeed, with the longitudinal feedback switched off, the
positron beam becomes unstable with beam currents in the order of 200-300 mA.
The longitudinal instability is damped by bringing the positron beam in
collision with a high current electron beam (~2A). Besides, we have observed a
shift of \approx 600Hz in the residual synchrotron sidebands. Precise
measurements have been performed by using both a commercial spectrum analyzer
and the diagnostics capabilities of the DA{\Phi}NE longitudinal bunch-by-bunch
feedback. This damping effect has been observed in DA{\Phi}NE for the first
time during collisions with the crab waist scheme. Our explanation is that beam
collisions with a large crossing angle produce a longitudinal tune shift and a
longitudinal tune spread, providing Landau damping of synchrotron oscillations.Comment: 3 pages, 5 figures, talk presented to IPAC'10 - Kyoto - May 24-28
201
Aplication of Frequency Map Analysis to Beam-Beam Effects Study in Crab Waist Collision Scheme
We applied Frequency Map Analysis (FMA) - a method that is widely used to
explore dynamics of Hamiltonian systems - to beam-beam effects study. The
method turned out to be rather informative and illustrative in the case of a
novel Crab Waist collision approach, when "crab" focusing of colliding beams
results in significant suppression of betatron coupling resonances. Application
of FMA provides visible information about all working resonances, their widths
and locations in the planes of betatron tunes and betatron amplitudes, so the
process of resonances suppression due to the beams crabbing is clearly seen.Comment: 11 pages, 10 figure
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