1,688 research outputs found
Photon production at the interaction point of the ILC
The intense beam-beam effect at the interaction point of the International
Linear Collider (ILC) causes large disruption of the beams and the production
of photons. These photons, arising dominantly through beamstrahlung emission,
are problematic for the machine design as they need to be transported and
dumped in a controlled way. In this work, we perform simulations of the
beam-beam interaction to predict photon production rates and distributions for
the different beam parameters considered at ILC. The results are expressed in
terms of a set of cones of excluded power, allowing to define the
beam-stay-clear requirements relevant for different cases and contexts. A
comparison is also made with theoretical expectations. The suggested photon
cone half-opening angles are 0.75 and 0.85 mrad in the horizontal and vertical
planes, respectively. These cones cover all machine energies and parameter
sets, and include the low power Compton photons
2D-Oide effect
The Oide effect considers the synchrotron radiation in the final focusing
quadrupole and it sets a lower limit on the vertical beam size at the
Interaction Point, particularly relevant for high energy linear colliders. The
theory of the Oide effect was derived considering only the radiation in the
focusing plane of the magnet. This article addresses the theoretical
calculation of the radiation effect on the beam size consider- ing both
focusing and defocusing planes of the quadrupole, refered to as 2D-Oide. The
CLIC 3 TeV final quadrupole (QD0) and beam parameters are used to compare the
theoretical results from the Oide effect and the 2D-Oide effect with particle
tracking in PLACET. The 2D-oide demonstrates to be important as it increases by
17% the contribution to the beam size. Further insight into the aberrations
induced by the synchrotron radiation opens the possibility to partially correct
the 2D-Oide effect with octupole mag
Experimental Implications for a Linear Collider of the SUSY Dark Matter Scenario
This paper presents the detection issues for the lightest slepton
\tilde{\tau}_1 at a future e^+e^- TeV collider given the dark matter
constraints set on the SUSY mass spectrum by the WMAP results. It intends to
illustrate the importance of an optimal detection of energetic electrons in the
very forward region for an efficient rejection of the
\gamma\gamma background. The TESLA parameters have been used in the case of
head-on collisions and in the case of a 10, mrad half crossing angle.Comment: 24 pages, 13 figures, Work presented at the International Conference
on Linear Colliders (LCWS04), 19-23 April 2004, Le Carre des Sciences, Paris,
Franc
Particle tracking in the ILC extraction lines with DIMAD and BDSIM
The study of beam transport is of central importance to the design and
performance assessment of modern particle accelerators. In this paper, we
benchmark two contemporary codes, DIMAD and BDSIM, the latter being a
relatively new tracking code built within the framework of GEANT4. We consider
both the 20 mrad and 2 mrad extraction lines of the 500 GeV International
Linear Collider (ILC) and we perform particle tracking studies of heavily
disrupted post-collision electron beams. We find that the two codes give an
almost equivalent description of the beam transport
Benchmarking of Tracking Codes (BDSIM/DIMAD) using the ILC Extraction Lines
The study of beam transport is of central importance to the design and
performance assessment of modern particle accelerators. In this work, we
benchmark two contemporary codes - DIMAD and BDSIM, the latter being a
relatively new tracking code built within the framework of GEANT4. We consider
both the 20 mrad and 2 mrad extraction lines of the International Linear
Collider (ILC) and we perform tracking studies of heavily disrupted
post-collision electron beams. We find that the two codes mostly give an
equivalent description of the beam transport.Comment: Contribution to the Tenth European Particle Accelerator Conference
`"EPAC'06'', Edinburgh, United-Kingdom, 26-30 June 200
Fast Luminosity Monitoring using Diamond Sensors for Super Flavour Factories
MOPME004 - ISBN 978-3-95450-122-9International audienceSuper flavour factories aim to reach very high luminosities thanks to a new concept whereby the ultra-low emittance beams collide with a large crossing angle. Fast luminosity measurements are needed as input to luminosity optimization and feedback in the presence of dynamic imperfections. The required small relative precision can be reached exploiting the very large cross section of the radiative Bhabha process at zero photon scattering angle. The instrumental technique selected to sustain the large particle fluxes is based on diamond sensors to be positioned viamoveable stages immediately outside the beam pipe, at locations chosen to minimize the contamination from other particle loss mechanisms
Study of time-dependent corrections in the ATF2 beam-line
International audienceGoals of ATF2 will be to provide beams with a few tens of nanometers and stability at the nanometer level. To achieve this, ground motion should be measured and the effects of element displacement on the beam at the Interaction Point (IP) should be well understood. Feedback systems should also be simulated with a gound motion generator which includes spatial coherence for effects to be computed realistically
Optical configurations with variable β* at different IP locations in ATF2
During ATF2 commissioning, it will be important to focus the beam to a proper waist at IP locations both upstream and downstream of the nominal one, where different beam size monitors will be placed with typical resolutions larger than that of the Shintake monitor at the nominal IP. In this note, a method to obtain optical configurations with variable β* at these different IP locations is described, enabling to match the measurement resolutions of these monitors with the linear beam size at the waist, while attempting to retain the overall features of the local chromaticity correction in the final focus optics. During commissioning, it is expected that one will gradually reduce β* after measurements at these different locations
The Impact of BeamCal Performance at Different ILC Beam Parameters and Crossing Angles on \tilde{tau} searches
The ILC accelerator parameters and detector concepts are still under
discussion in the world-wide community. As will be shown, the performance of
the BeamCal, the calorimeter in the very forward area of the ILC detector, is
very sensitive to the beam parameter and crossing angle choices. We propose
here BeamCal designs for a small (0 or 2 mrad) and large (20 mrad) crossing
angles and report about the veto performance study done. As illustration, the
influence of several proposed beam parameter sets and crossing-angles on the
signal to background ratio in the stau search is estimated for a particular
realization of the super-symmetric model.Comment: Talk given by V. Drugakov at the Linear Collider Workshop "LCWS06'',
9-13 March 2006, I.I.Sc Bangalore, Indi
Backscattering of secondary particles into the ILC detectors from beam losses along the extraction line
online : http://cern.ch/AccelConf/p07/PAPERS/THPMN009.PDFInternational audienceAt the International Linear Collider (ILC) the beams will be focused to extremely small spot sizes in order to achieve the desired luminosity. After the collision the beams must be brought to the dump with minimal losses. In spite of all the attention put into the design of the extraction line, the loss of some disrupted beam particles, beamstrahlung or synchrotron radiation photons is unavoidable. These losses will generate low-energy secondary particles, such as photons, electrons and neutron, a fraction of which can be back-scattered towards the Interaction Point (IP) and generate backgrounds into the detector. In this paper we present an evaluation of such backgrounds, using the BDSIM [1] and Mokka [2] simulations. The event reconstruction in the detector is made with the MarlinReco package from the Marlin tool [3]
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