Design of PIP-II Medium Energy Beam Transport

The Proton Improvement Plan-II (PIP-II) is a proposed upgrade for the accelerator complex at Fermilab. The central piece of PIP-II is a new superconducting radio frequency (SRF) 800 MeV linear accelerator (linac) capable of operating in both continuous wave (CW) and pulse regimes. The PIP-II linac comprises a warm front-end that includes a Hion source capable of delivering 15-mA, 30keV DC or pulsed beam, a Low Energy Beam Transport (LEBT), a 162.5 MHz, CW Radio-Frequency Quadrupole (RFQ) accelerating the ions to 2.1 MeV and, a 14-m Medium Energy Beam Transport (MEBT) before beam is injected into SRF part of the linac. This paper presents the PIP-II MEBT design and, discusses operational features and considerations that lead to existing optics design such as bunch by bunch chopping system, minimization of radiation coming to the warm front-end from the SRF linac using a concrete wall, a robust vacuum protection system etc.