The device through which protons are delivered to the patient. At Loma Linda, proton beam delivery begins in the accelerator, where an ion source generates protons. The accelerator (synchrotron) energizes the protons to a prescribed energy and sends them to the beam transport system, which sends the beam to the treatment rooms. Each treatment room has a nozzle, which looks much like the nozzle of a water hose and is the final element in the beam delivery system. The nozzle not only delivers the beam to the patient, but also monitors beam uniformity, alignment, and dose delivered.