Luc Sermeus

160 MeV H - injection into the CERN PSB

The H- beam from the proposed LINAC4 will be injected into the four existing rings of the PS Booster at 160 MeV. A substantial upgrade of the injection region is required, including the modification of the beam distribution system and the construction of a new H- injection system. This paper discusses beam dynamics and hardware requirements and presents the results of optimisation studies of the injection process for different beam characteristics and scenarios. The resulting conceptual design of the injection region is presented, together with the main hardware modifications and performance specifications.

Pulse Forming Network Conceptual Design for the Proposed PS Multi-Turn Extraction System

A five-turn continuous extraction system is currently used to transfer the proton beam from the CERN Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS). The present approach, which is based on cutting the filament beam into 5 slices using an electrostatic septum, causes inherent losses of about 15% of the extracted beam and non optimal betatronic matching for the different slices in the receiving machine. This will be an even more serious drawback when the beam intensity needs to be increased for the CERN Neutrinos to Gran Sasso (CNGS) facility. To overcome this, a novel multi-turn extraction (MTE) scheme has been proposed, where the beam is separated, prior to extraction, into a central beam core and four islands by means of elements such as sextupoles and octupoles. Each beamlet is ejected using fast kickers and a magnetic septum. For the MTE kickers, two new pulse generators are required, each containing a lumped element Pulse Forming Network (PFN) of 12.5 Omega, 80 kV and 10.5 mus. For cost reasons, it is envisaged to re-use existing 15 Omega transmission line kicker magnets. The PFN characteristic impedance deliberately mismatches that of the magnets to allow a higher maximum available kick. The PFN design has been optimized such that undesirable side-effects of the impedance mismatch, on kick rise-time and flat-top, remain within acceptable limits. The conceptual design for the MTE PFN is presented.

Kickers used for bunched e/sup +//e/sup -/ beam transfer in the CERN PS complex

The main characteristics and operating experiences of the 100-Hz pulsed injection kicker and the eight pulse burst ejection kicker systems installed in the EPA (Electron Positron Accumulator) ring are described. Delay line type magnets placed in vacuum tanks are excited by fast pulses generated from thyratron-switched PFNs (pulse forming networks). Deflecting fields of 52 ns FWHH with rise and fall times of 28 ns are achieved. Up to eight e/sup +/ or e/sup -/ bunches are injected into the PS (Proton Synchrotron) in a single turn. For each particle type, one delay-line-type magnet is used. Both magnets are excited from the same PFN, switched at either end, with a pulse of 2000 A and 2 mu s duration. A transfer efficiency between EPA and PS exceeding 90% has been achieved.<<ETX>>

Machine development studies for PSB extraction at 160 MeV and PSB to PS beam transfer

This paper collects the machine development (MD) activities for the beam transfer studies in 2016 concerning the PSB extraction and the PSB-to-PS transfer. Many topics are covered: from the 160 MeV extraction from the PSB, useful for the future commissioning activities after the connection with Linac4, to new methodologies for measuring the magnetic waveforms of kickers and dispersion reduction schemes at PS injection, which are of great interest for the LHC Injectors Upgrade (LIU) [1] project.

PPPS-2013: Design and development of a 6.25 kV / 1 kA PFN to supply the new PS Booster distributor magnets

Linac4 is an H- ion linear accelerator, intended to replace Linac2 as injector to the PS Booster (PSB). In order to distribute the 160 MeV beam from Linac4 to the four rings of the PSB, new distributor magnets (BI.DIS) and magnetic septa (BI.SMV) need to be built. The proposed distribution scheme requires the construction of five new pulse generators, of Pulse Forming Network (PFN) type, to double the magnitude of the BI.DIS field pulse and to increase the maximum duration of the pulse from 140 μs to 620 μs.