Fermilab, Batavia, Illinois, USA
NSCL, East Lansing, Michigan, USA
BARC, Mumbai, India
The Proton Improvement Plan, Stage Two (PIP-II) is a program of upgrades proposed for the Fermilab injection complex, which central part is an 800-MeV, 2-mA CW SRF linac. A prototype of the PIP-II linac front end called PIP-II Injector Test (PIP2IT) is being built at Fermilab. As of now, a 15-mA DC, 30-keV H− ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1-MeV CW RFQ, followed by a 10-m Medium Energy Beam Transport (MEBT) have been assembled and commissioned. The MEBT bunch-by-bunch chopping system and the requirement of a low uncontrolled beam loss put stringent limitations on the beam envelope and its variation. Measurements of transverse and longitudinal beam dynamics in the MEBT were performed in the range of 1-10 mA of the RFQ beam current. Almost all measurements are made with 10 μs beam pulses in order to avoid damage to the beam line. This report presents measurements of the transverse optics with differential trajectories, reconstruction of the beam envelope with scrapers and an Allison emittance scanner, as well as bunch length measurements with a Fast Faraday Cup.
Fermilab, Batavia, Illinois, USA
NSCL, East Lansing, Michigan, USA
RRCAT, Indore (M.P.), India
The PIP-II program of upgrades proposed for the Fermilab accelerator complex, is centered around a 800 MeV, 2 mA CW SRF linac. A unique feature of the PIP-II linac is the capability to form a flexible bunch structure by removing a pre-programmed set of bunches from a long-pulse or CW 162.5 MHz train, coming from the RFQ, within the 2.1-MeV Medium Energy Beam Transport (MEBT) section. The MEBT chopping system consists of two travelling-wave kickers working in sync followed by a beam absorber. The prototype components of the chopping system, two design variants of the kickers and a 1/4-size absorber, have been installed in the PIP-II Injector Test (PIP2IT) accelerator and successfully tested with beam of up to 5 mA. In part, one of the kickers demonstrated a capability to create an aperiodic pulse sequence suitable for synchronous injection into the Booster while operating at 500 V and average switching frequency of 44 MHz during 0.55 ms bursts at 20 Hz. This report presents the design of the PIP-II MEBT chopping system and results of prototypes testing at PIP2IT.