Multiple volume reflections of high-energy protons in a sequence of bent silicon crystals assisted by volume capture

Multiple volume reflections of the 400 GeV/c proton beam by the sequence of fourteen bent silicon strips has been studied at the CERN SPS. The sequence is close to be parallel that is the spread of the strip orientation angles is much smaller than their bend angle and eleven strips working coherently in the regime of volume reflections deflected the beam by 110 mu rad with the efficiency 88%, which is significantly larger than the estimation based on independent reflections. The mechanism giving the efficiency increase has been studied by simulation. It appears that many particles volume captured in one of the strips take part in volume reflections in the subsequent ones. Such a crystal multi reflector can be successfully used as a primary collimator for the beam halo collimation of high-energy accelerators

Observation of multiple volume reflection by different planes in one bent silicon crystal for high-energy negative particles

Multiple volume reflection by different planes passing through the axis in a bent silicon crystal was observed for the first time for 150 GeV/c negative particles, pi(-) mesons, at one of the secondary beams of the CERN SPS. The beam of pi(-) mesons was deflected opposite to the crystal bend by an angle of about 48 mu rad, which is 4.6 times larger than in a single volume reflection by the (110) bent planes. The one-side deflection efficiency was about 65\%. Multiple volume reflection transforms to a single volume reflection when the orientation angle of the axis relative to the beam direction is increased. Copyright (c) EPLA, 201

Probability of inelastic nuclear interactions of high-energy protons in a bent crystal

Probability of inelastic nuclear interactions in a short bent silicon crystal for its orientations optimal for channeling and volume reflection was investigated using 400 GeV/c protons of the CERN SPS. The contribution of nuclear interactions from channeled protons was observed to be about 3-4% of the probability for the amorphous orientation. For the crystal orientation optimal for volume reflection the nuclear interaction probability of protons was a few percents larger than in the amorphous case It was shown that in the limiting case of a quasi parallel beam realizing for the collider beam halo the inelastic nuclear losses should decrease by more than five times, which is an additional advantage of a crystal as a primary collimator for the LHC collimation system

First observation of multiple volume reflection by different planes in one bent silicon crystal for high-energy protons

Multiple volume reflection by different planes in a bent silicon crystal with its axis orientation close to the beam direction was observed for the first time for 400 GeV/c protons at the CERN SPS. The proton beam was deflected to the side opposite to the crystal bend by an angle of about 67 urad, which is five times larger than in a single volume reflection by the (110) bent planes. The registered efficiency of one side deflection was about 84%. It was shown that multiple volume reflection transforms to a single volume reflection when the orientation angle of the axis relative to the beam direction is increased

计划与市场相结合的金融调控机制初探

本文试图通过对计划与市场这两种经济调节手段的研究，探索 金融领域中英立两者有机结合。金融调控机制的途径．文章先从。 究计划与市场的涵义及两者的关系人手，探讨金融调控中运用这两 种手段的必要性与可能性，再从计划与市场的最佳结合方式看眼， 找出金融调控中计划与市场有机结合的难点与重点，继两结合分析 我国中央银行现行调控手段的弊端，深入详尽地探讨难点的解决办 法，重点提出培育金融市场机制和完善信贷计划手段的对策，最后 沿着这一思路，进行建立我国计划与市场有机结合的金融调控机制 的构想。 全文共分四个部分．＿ 第一部分通过对计划，市场所下定义，明确两者都去经济调节 手段，并非相互...学位：经济学硕士院系专业：经济学院财政金融系_金融学(含保险学)学号：YL00012

Deflection of 400 GeV/c proton beam with bent silicon crystals at the CERN Super Proton Synchrotron

This paper presents a detailed study of the deflection phenomena of a 400 GeV/c proton beam impinging on a new generation of bent silicon crystals; the tests have been performed at the CERN Super Proton Synchrotron H8 beam line. Channeling and volume reflection angles are measured with an extremely precise goniometer and with high resolution silicon microstrip detectors. Volume reflection has been observed and measured for the first time at this energy, with a single-pass efficiency as large as 98%, in good agreement with the simulation results. This efficiency makes volume reflection a possible candidate for collimation with bent crystals at the CERN Large Hadron Collider