Apparatus to study crystal channeling and volume reflection phenomena at the SPS H8 beamline

Scandale, W.; Efthymiopoulos, I.; Still, D. A.; Carnera, A.; Della Mea, Gianantonio; De Salvador, D.; Milan, R.; Vomiero, A.; Baricordi, S.; Chiozzi, S.; Dalpiaz, P.; Damiani, C.; Fiorini, M.; Guidi, V.; Martinelli, G.; Mazzolari, A.; Milan, E.; Ambrosi, G.; Azzarello, P.; Battiston, Roberto; Bertucci, B.; Burger, W. J.; Ionica, M.; Zuccon, P.; Cavoto, G.; Santacesaria, R.; Valente, P.; Vallazza, E.; Afonin, A. G.; Baranov, V. T.; Chesnokov, Y. u. A.; Kotov, V. I.; Maisheev, V. A.; Yazynin, I. A.; Afanasiev, S. V.; Kovalenko, A. D.; Taratin, A. M.; Bondar, N. F.; Denisov, A. S.; Gavrikov, Y. u. A.; Ivanov, Y. u. M.; Ivochkin, V. G.; Kosyanenko, S. V.; Lapina, L. P.; Levtchenko, P. M.; Petrunin, A. A.; Skorobogatov, V. V.; Suvorov, V. M.; Bolognini, D.; Foggetta, L.; Hasan, S.; Prest, M.

doi:10.1063/1.2832638

A high performance apparatus has been designed and built by the H8-RD22 collaboration for the study of channeling and volume reflection phenomena in the interaction of 400 GeVc protons with bent silicon crystals, during the 2006 data taking in the external beamline H8 of the CERN SPS. High-quality silicon short crystals were bent by either anticlastic or quasimosaic effects. Alignment with the highly parallel _8 _rad divergence_ proton beam was guaranteed through a submicroradian goniometric system equipped with both rotational and translational stages. Particle tracking was possible by a series of silicon microstrip detectors with high-resolution and a parallel plate gas chamber, triggered by various scintillating detectors located along the beamline. Experimental observation of volume reflection with 400 GeVc protons proved true with a deflection angle of _10.4_0.5_ _rad with respect to the unperturbed beam, with a silicon crystal whose _111_ planes were parallel to the beam.