2,077 research outputs found
Bent crystals for efficient beam steering of multi TeV-particle beams
Charged particle beams can be manipulated by exploiting the channeling phenomenon in bent crystals. Two plate-like crystals, bent by mechanical holders, were manufactured and characterised for such purpose at the Sensor and Semiconductor Laboratory in Ferrara, Italy. An anticlastic curvature was obtained for these crystals, achieving a steering angle of the order of 1 mrad, which is about 20 times larger than the values currently achieved for the bent crystals used in the LHC for collimation experiments. Finally, a Geant4 simulation was performed to study the channeling efficiency for beam deflection with 400 GeV/c and 7 TeV/c proton beams. Such crystals represent technological progress in the development of bent crystals for highly energetic charged particle beams. Indeed, they are designed to impart an angular kick to a 7 TeV/c proton beam with unprecedented high efficiency. Therefore, this study demonstrates the possibility of realizing bent crystals suitable for beam extraction in high-energy hadron accelerators, such as LHC or at the future FCC. A further series of studies should be conducted to evaluate the channeling efficiency and the deflection angle of the realized crystals via a charged proton beam
BaBar forward endcap RPCs
Abstract The BaBar detector has operated over 2000 m 2 of resistive plates chambers (RPCs) as muon and neutral hadron detectors since 1999. Most of the RPCs of the original production underwent a significant efficiency loss and many are now completely inefficient. During the summer 2002 new RPCs from a recent production were therefore installed to replace the old chambers in the forward endcap. The experience of the first 8 months of operation is described here
Characterisation of the fused silica surface quality with a β-source
A method to characterise the quality of a fused silica surface using a β-source is presented. Two fused silica bars (5×10×400mm3) were fabricated for the Cherenkov detector for proton Flux Measurement installed at vacuum chamber of the Super Proton Synchrotron at CERN. The resolution of such device is defined by the collection efficiency of the Cherenkov light, which is produced by relativistic charged particles in the fused silica. Thus, the surface quality of the radiator should be as good as possible to avoid light losses. The method is based on the scanning of the radiator surface with a90Sr radioactive source and measurements of the Cherenkov light rate, detected by a PMT attached to the quartz bars. The data have been compared with a Monte-Carlo simulation, providing an estimation of the radiator's probability of the total internal reflection and inefficient area at the edges of the bars
Sub-GeV Dark Matter Detection with Electron Recoils in Carbon Nanotubes
Directional detection of Dark Matter particles (DM) in the MeV mass range
could be accomplished by studying electron recoils in large arrays of parallel
carbon nanotubes. In a scattering process with a lattice electron, a DM
particle might transfer sufficient energy to eject it from the nanotube
surface. An external electric field is added to drive the electron from the
open ends of the array to the detection region. The anisotropic response of
this detection scheme, as a function of the orientation of the target with
respect to the DM wind, is calculated, and it is concluded that no direct
measurement of the electron ejection angle is needed to explore significant
regions of the light DM exclusion plot. A compact sensor, in which the cathode
element is substituted with a dense array of parallel carbon nanotubes, could
serve as the basic detection unit.Comment: 8 pages, 4 figures; updated and improved version to appear in Phys.
Lett.
Angles from B Decays with Charm: Summary of Working Group 5 of the CKM Workshop 2006
We summarize the results presented in Working Group 5 (WG5) of the CKM 2006
Workshop in Nagoya. The charge of WG5 was to discuss the measurements of
unitarity triangle angles and from -meson
decays containing charm quark(s) in the final states.Comment: 9 pages, 8 postscript figures, to appear in the proceedings of 4th
International Workshop on the CKM Unitarity Triangle (CKM 2006), Nagoya,
Japan, 12-16 Dec 200
Negative ion Time Projection Chamber operation with SF at nearly atmospheric pressure
We present measurements of drift velocities and mobilities of some innovative
negative ion gas mixtures at nearly atmospheric pressure based on SF as
electronegative capture agent and of pure SF at various pressures,
performed with the NITEC detector. NITEC is a Time Projection Chamber with 5 cm
drift distance readout by a GEMPix, a triple thin GEMs coupled to a
Quad-Timepix chip, directly sensitive to the deposited charge on each of the 55
55 m pixel. Our results contribute to expanding the knowledge
on the innovative use of SF as negative ion gas and extend to triple thin
GEMs the possibility of negative ion operation for the first time. Above all,
our findings show the feasibility of negative ion operation with
He:CF:SF at 610 Torr, opening extremely interesting possibility for
next generation directional Dark Matter detectors at 1 bar
Carbon nanotubes as target for directional detection of light WIMP
In this paper I will briefly introduce the idea of using Carbon Nanotubes
(CNT) as target for the detection of low mass WIMPs with the additional
information of directionality. I will also present the experimental efforts of
developing a Time Projection Chamber with a CNT target inside and the results
of a test beam at the Beam Test Facility of INFN-LNF.Comment: 3 figures, IFAE2017 poster session proceeding
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