We present the experimental observation of the reduction of multiple scattering of high-energy positively charged particles during channeling in single crystals. According to our measurements the rms ...angle of multiple scattering in the plane orthogonal to the plane of the channeling is less than half that for non-channeled particles moving in the same crystal. In the experiment we use focusing bent single crystals. Such crystals have a variable thickness in the direction of beam propagation. This allows us to measure rms angles of scattering as a function of thickness for channeled and non-channeled particles. The behaviour with thickness of non-channeled particles is in agreement with expectations whereas the behaviour of channeled particles has unexpected features. We give a semi-quantitative explanation of the observed effect.
In this paper, we discuss an experimental layout for the two-crystals scenario at the Super Proton Synchrotron (SPS) accelerator. The research focuses on a fixed target setup at the circulating ...machine in a frame of the Physics Beyond Colliders (PBC) project at CERN. The UA9 experiment at the SPS serves as a testbench for the proof of concept, which is planning to be projected onto the Large Hadron Collider (LHC) scale. The presented in the text configuration was used for the quantitative characterization of the deflected particle beam by a pair of bent silicon crystals. For the first time in the double-crystal configuration, a particle deflection efficiency by the second crystal of \(0.188 \pm 3 \cdot 10^{-5}\) and \(0.179 \pm 0.013\) was measured on the accelerator by means of the Timepix detector and Beam Loss Monitor (BLM) respectively. In this setup, a wide range angular scan allowed a possibility to \textit{in situ} investigate different crystal working regimes (channeling, volume reflection, etc.), and to measure a bent crystal torsion.
An interesting method of bending silicon crystal plates by scratching the grooves on the surface mechanically has been presented in the paper. This method appears to have considerable promise for ...both the U70 accelerator at the Institute for High Energy Physics and the devices at the Large Hadron Collider (LHC). Using the method mentioned above, specific devices were made: a crystalline undulator for 3 GeV positrons, short crystalline deflectors for extraction of 70 GeV proton beam from the U70 accelerator, and multistrip crystals for collimating the 6500 GeV proton beam into the LHC. В статье описан интересный метод изгиба кристаллических пластин кремния с помощью нанесения механическим путем канавок на их поверхности. Метод перспективен для применения как в ускорителе У70 Института физики высоких энергий, так и в устройствах Большого адронного коллайдера (БАК). С использованием указанного метода созданы конкретные устройства: кристаллический ондулятор для пучка позитронов с энергией 3 ГэВ, короткие кристаллические дефлекторы для вывода пучка протонов с энергией 70 ГэВ из ускорителя У70, многополосковые кристаллы для коллимации пучка протонов в БАК при энергии 6500 ГэВ.
Recently it was proposed to apply a bent single crystal with decreasing curvature instead of uniform bending for improvement of extraction and collimation of a circulating beam in particle ...accelerators. In the given paper created crystal devices with a variable curvature, realizing this idea are described. Results of measurement of curvature along a crystal plate are informed. It is shown, that with the help of the developed devices it is possible to carry out also high energy beam focusing. The mathematical description of this process is proposed.
The bent crystals are applied on large accelerators to deflect particle beams in process of extraction and collimation. Recently the proposals of fixed target researches in the LHC are formulated. ...For realization of this program not only deflection but also focusing the LHC beam by bent crystals can be used. In the given work experimental results on 50 GeV proton beam focusing with the help of novel crystal device are reported. The positive property of this device is opportunity to work near the circulating beam of an accelerator, including the LHC.
