Generation and Benefits of Long Super-Bunches

To maximize the luminosity of the Large Hadron Collider (LHC) bunches with a uniform longitudinal line density are considered for a future upgrade. In the first part three different options will be presented: short rectangular bunches held by multiple RF harmonics using multiples of 400 MHz, long and flat bunches held by multiples of 40 MHz and the so-called super-bunches which are confined by barrier buckets. The potential luminosity improvement of these options with respect to the beam-beam limit will be analyzed. The second part will be dedicated tothe generation of the bunches with uniform line density by appropriate RF manipulations. It will be shown that especially the scheme to create long and flat bunches at multiples of 40 MHz relies on well proven RF techniques and can be performed in the LHC with additional RF hardware of reasonable size and performance.