A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Bagli, E.

Paper Title Page
TUPEA070 ECHARM - a Software for Calculation of Physical Quantities of Interest in Coherent Interaction of Relativistic Particles with Crystals 1485
 
  • E. Bagli
    INFN-Ferrara, Ferrara
  • V. Guidi
    UNIFE, Ferrara
  • V.A. Maisheev
    IHEP Protvino, Protvino, Moscow Region
 
 

We present an analytical model to calculate the physical quantities of interest experienced by relativistic particles in their motion aligned with periodic complex atomic structures. Classical physics equations and the expansion of periodic functions as a Fourier series have been used for the calculation. This method allows calculating the contribution from all the planes and axes inside the crystal, in contrast to other simulation codes for which the motion is evaluated only on nearest neighbors atomic strings. Based on the calculation technique we have developed the "ECHARM" program, which allows calculating one- and two- dimensional averaged physical quantities of interest. The calculation holds for the main axes of any orthorhombic and tetragonal structures and for any orientation in the cubic structure. To underline the capability of the program, complex structures such as zeolites have been worked out. Based on the "ECHARM" code, simulation of the relativistic particle motion within complex structures has been developed. With this code it is possible to simulate the motion in bent crystal to study planar and axial channeling volume reflection.

 
THPEC080 Fabrication of Silicon Strip Crystals for UA9 Experiment 4243
 
  • A. Mazzolari, E. Bagli, V. Guidi
    INFN-Ferrara, Ferrara
  • S. Baricordi, P. Dalpiaz, D. Vincenzi
    UNIFE, Ferrara
  • A. Carnera, D. De Salvador
    Univ. degli Studi di Padova, Padova
  • G. Della Mea
    INFN/LNL, Legnaro (PD)
  • A.M. Taratin
    JINR, Dubna, Moscow Region
 
 

Channeling in bent crystals is a technique with high potential to steer charged-particle beams for several applications in accelerators physics. Revisited methods of silicon micromachining techniques allowed one to realize a new generation of crystals. Characterizations using x-ray diffraction, atomic force microscopy, high resolution transmission electron microscopy and ion beam analysis techniques, showed high quality of the crystals. A specifically designed holder allowed to mechanically bend a crystal at given curvature and remove unwanted torsion. Characterization of such crystals with 400 GeV at CERN H8 external line highlighted 85% single-pass efficiency. A selected crystal has been installed inside the SPS ring in the environment of the CERN experiment UA9 and successfully employed for collimation of the circulating beam.


On behalf of UA9 collaboration

 
THPD052 Manipulation of Negatively Charged Beams via Coherent Effects in Bent Crystals 4398
 
  • V. Guidi, E. Bagli, A. Mazzolari
    INFN-Ferrara, Ferrara
  • A.G. Afonin, Y.A. Chesnokov, V.A. Maisheev, I.A. Yazynin
    IHEP Protvino, Protvino, Moscow Region
  • S. Baricordi, P. Dalpiaz, M. Fiorini, D. Vincenzi
    UNIFE, Ferrara
  • D. Bolognini, S. Hasan, M. Prest
    Università dell'Insubria & INFN Milano Bicocca, Como
  • G. Della Mea, R. Milan
    INFN/LNL, Legnaro (PD)
  • A.S. Denisov, Yu.A. Gavrikov, Yu.M. Ivanov, L.P. Lapina, L.G. Malyarenko, V. Skorobogatov, V.M. Suvorov, S.A. Vavilov
    PNPI, Gatchina, Leningrad District
  • S. Golovatyuk, A.D. Kovalenko, A.M. Taratin
    JINR, Dubna, Moscow Region
  • A. Mattera
    INFN MIB, MILANO
  • W. Scandale
    CERN, Geneva
  • S. Shiraishi
    Enrico Fermi Institute, University of Chicago, Chicago, Illinois
  • E. Vallazza
    INFN-Trieste, Trieste
  • A. V. Vomiero
    INFM-CNR, Istituto Nazionale di Fisica della Materia - Consiglio Nazionale delle Ricerche, Brescia
 
 

New results in coherent interaction of negatively-charged particles with bent crystals showed unprecedentedly and significantly high efficiency to manipulate such beams, in the same way as for positively charged particles. Key feature under experimental attainment was the usage of high-quality suitably thin silicon crystals. We experimentally tested crystals Vs. 150 GeV negative pions at external lines of CERN SPS. We observed planar channeling at full deflection angle 30% high single-pass efficiency and large acceptance (about 20μrad). Moreover in the axial case, we reached more than 90% deflection efficiency and larger acceptance (about 60μrad). We also observed volume reflection in a bent crystal, at more than 70% single-pass efficiency with such a wide acceptance as the bending angle. At last, volume reflection by several planes in a single bent crystal was successfully tested with very high efficiency (about 80%). In summary both channeling and volume reflection modes appear to be useful technique for the manipulation of negatively charged beams, e.g. for collimation in the new generation of high intensity accelerators.


The UA9 collaboration