Synchrotrotron Radiation in the LHC Experimental Insertions

Synchrotron radiation in the LHC experimental insertions was simulated using the code PHOTON for the LHC optics version 6.4, considering realistic apertures for all beam-line elements. The simulations computed the incident flux of photons, the local heat load, and the average photon energy as a function of position along the beam line, for two different photon reflectivities in the long straight sections, with or without radiation in the quadrupoles, and for either of the two beams. The effect of large optics errors was also explored. This study shows that the photon flux in the experimental insertions is about 20 times smaller than in the arcs. The average photon energy is reduced by a factor 2.5 as well. The results are insensitive to the optics. A sawtooth chamber with reduced photon reflectivity would alter the photon flux only marginally