The New ISR Absorber Blocks for High Intensity Beams

With the continual improvement of the ISR, one may hope that proton beams of intensities greater than 50 A (2.5 times the design value) will soon be obtained. The kinetic energy stored will then be 4 MJ and the instantaneous power at dumping greater than 1.3 Terawatt. New absorber blocks, able to stop 26 GeV/c beams of intensities up to 80 A, have been installed in the ISR in 1979. This paper describes the technical solutions adopted taking into account space, vacuum and operational constraints. Choice of materials criteria for the block itself, the vacuum chamber and the associated collimator are also presented.