Homenageando Herbert Moritz Caro

This text offers a closer look at Herbert Caro’s life, habits and his role as one of the founders of the Jewish Foundation SIBRA in Porto Alegre

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

The Injection System of the INFN-SuperB Factory Project: Preliminary Design

THPEA007International audienceThe ultra high luminosity B-factory (SuperB) project of INFN requires a high performance and reliable injection system, providing electrons at 4 GeV and positrons at 7 GeV, to fulfill the very tight requirements of the collider. Due to the short beam lifetime, continuous injection of electrons and positrons in both HER and LER rings is necessary to keep the average luminosity at a high level. Polarized electrons are required for experiments and must be delivered by the injection system, due to the beam lifetime shorter than the polarization build-up: they will be produced by means of a SLAC-SLC polarized gun. One or two 1 GeV damping rings are used to reduce e+ and e- emittances. Two schemes for positron production are under study, one with electron-positron conversion at low energy (<1 Gev), the second at 6 GeV with a recirculation line to bring the positrons back to the damping ring. Acceleration through the Linac is provided by a S-band RF system made of traveling wave, room temperature accelerating structures. An option to use the C-band technology is also presented

Positron Production and Capture based on Low Energy Electrons for SuperB

TUPEB057International audienceProviding a high quality and sufficient high current positron beam for the ultra high luminosity B-factory SuperB is a major goal. In this paper a proposition for positrons production and capture scheme based on low energy electrons up to1 GeV is presented. For this technique, several types of flux concentrator used to capture the positrons are being studied. The following accelerating section bringing the positrons up to 280 MeV and the total yield for L-band and S-band type accelerators are given. Also the result of the benchmark between ASTRA and a LAL code based on Geant4 toolkit simulation is discussed

Generation of Engineered Aerosol Stainless Steel Nanoparticles using a Spark Discharge Generator

This diploma work has shown that it is possible to generate engineered stainless steel nanoparticles using a spark discharge generator (SDG) with a selectable size in the size range 20-70 nm in diameter. The generated particles have similar composition as the electrodes used, although further studies are needed to verify if this is true for all particles generated. If this is true, it would be possible to produce nanoparticles of any type of stainless steel alloy - the only prerequisite is that it exists in bulk form. The most suitable operating parameters for the generation have been determined to: 2 mm gap distance between the electrodes and 10 mA charging current when the capacitance was 21 nF. The compaction temperature was determined to be approximately 1200$^{\circ}$C when 50 nm agglomerates were compacted in nitrogen. It is still uncertain whether it exists a protective chromium oxide layer surrounding each particle and making it corrosion resistant. The chromium content in the particles indicates that there might be and the particles are stable in air but more research is needed to conclude this. A complete study on engineered stainless steel nanoparticles has not been performed and more research needs to be done, different types of carrier gas need to be tested to optimize for higher concentration, lower compaction temperature and avoiding possible nitride formation and oxidation. Also, more TEM and XEDS studies need to be performed in order to determine the average composition of the nanoparticles. An experiment when these nanoparticles were used to enhance sintering behavior of a micro-powder was initiated but not completed and needs to be investigated further. The results in this work can be used as a base for further studies on engineered stainless steel nanoparticles

Status of the Super-B factory Design

The SuperB international team continues to optimize the design of an electron-positron collider, which will allow the enhanced study of the origins of flavor physics. The project combines the best features of a linear collider (high single-collision luminosity) and a storage-ring collider (high repetition rate), bringing together all accelerator physics aspects to make a very high luminosity of 10$^{36}$ cm$^{-2}$ sec$^{-1}$. This asymmetric-energy collider with a polarized electron beam will produce hundreds of millions of B-mesons at the $\Upsilon$(4S) resonance. The present design is based on extremely low emittance beams colliding at a large Piwinski angle to allow very low $\beta_y^\star$ without the need for ultra short bunches. Use of crab-waist sextupoles will enhance the luminosity, suppressing dangerous resonances and allowing for a higher beam-beam parameter. The project has flexible beam parameters, improved dynamic aperture, and spin-rotators in the Low Energy Ring for longitudinal polarization of the electron beam at the Interaction Point. Optimized for best colliding-beam performance, the facility may also provide high-brightness photon beams for synchrotron radiation applications

Commissioning Status of the CTF3 Delay Loop

The CLIC Test Facility CTF3, built at CERN by an international collaboration, aims at demonstrating the linear collider by 2010. In particular, one of the main goals is to study the generation of high-current electron pulses by interleaving bunch trains in delay lines and rings using transverse RF deflectors. This will be done in the 42 m long delay loop, built under the responsibility of INFN/LNF, and the 84 m long combiner ring that will follow it. The delay loop installation was completed and its commissioning started at the end of 2005. In this paper the commissioning results are presented, including the first tests of beam recombination

AGILE detection of delayed gamma-ray emission from GRB 080514B

GRB 080514B is the first gamma ray burst (GRB), since the time of EGRET, for which individual photons of energy above several tens of MeV have been detected with a pair-conversion tracker telescope. This burst was discovered with the Italian AGILE gamma-ray satellite. The GRB was localized with a cooperation by AGILE and the interplanetary network (IPN). The gamma-ray imager (GRID) estimate of the position, obtained before the SuperAGILE-IPN localization, is found to be consistent with the burst position. The hard X-ray emission observed by SuperAGILE lasted about 7 s, while there is evidence that the emission above 30 MeV extends for a longer duration (at least ~13 s). Similar behavior was seen in the past from a few other GRBs observed with EGRET. However, the latter measurements were affected, during the brightest phases, by instrumental dead time effects, resulting in only lower limits to the burst intensity. Thanks to the small dead time of the AGILE/GRID we could assess that in the case of GRB 080514B the gamma-ray to X-ray flux ratio changes significantly between the prompt and extended emission phase.Comment: A&A letters, in pres