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Observation of parametric X-rays produced by 400 GeV/c protons in bent crystals |
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| Affiliation: | a CERN, European Organization for Nuclear Research, CH-1211 Geneva 23, Switzerland b Laboratoire de l?Accelerateur Lineaire (LAL), Université Paris Sud Orsay, Orsay, France c INFN Sezione di Ferrara, Dipartimento di Fisica, Università di Ferrara, Ferrara, Italy d INFN LNF, Via E. Fermi, 40 00044 Frascati (Roma), Italy e INFN Laboratori Nazionali di Legnaro, Viale Università 2, 35020 Legnaro (PD), Italy f INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome, Italy g INFN Sezione di Napoli, Italy h Institute of High Energy Physics, RU-142284 Protvino, Moscow Region, Russia i Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region, Russia j Petersburg Nuclear Physics Institute, 188300 Gatchina, Leningrad Region, Russia k Imperial College, London, United Kingdom l Brookhaven National Laboratories, P.O. Box 5000 Upton, NY 11973-5000, USA m SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA n Institute in Physical and Technical Problems, 141980 Dubna, Moscow Region, Russia o Institute of Physics and Technology at TPU, 634050 Tomsk, Russia |
| Abstract: | Spectral maxima of parametric X-ray radiation (PXR) produced by 400 GeV/c protons in bent silicon crystals aligned with the beam have been observed in an experiment at the H8 external beam of the CERN SPS. The total yield of PXR photons was about 10−6 per proton. Agreement between calculations and the experimental data shows that the PXR kinematic theory is valid for bent crystals with sufficiently small curvature as used in the experiment. The intensity of PXR emitted from halo protons in a bent crystal used as a primary collimator in a circular accelerator may be considered as a possible tool to control its crystal structure, which is slowly damaged because of irradiation. The intensity distribution of PXR peaks depends on the crystal thickness intersected by the beam, which changes for different orientations of a crystal collimator. This dependence may be used to control crystal collimator alignment by analyzing PXR spectra produced by halo protons. |
| Keywords: | Crystal Proton Parametric X-ray radiation |
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