Yves Roblin

ER@CEBAF, a 7 GeV, 5-Pass, Energy Recovery Experiment

A multiple-pass, high-energy ERL experiment at the JLab CEBAF will be instrumental in providing necessary information and technology testing for a number of possible future applications and facilities such as Linac-Ring based colliders, which have been designed at BNL (eRHIC) and CERN (LHeC), and also drivers for high-energy FELs and 4th GLS. ER@CEBAF is aimed at investigating 6D optics and beam dynamics issues in ERLs, such as synchrotron radiation effects, emittance preservation, stability, beam losses, multiple-pass orbit control/correction, multiple-pass beam dynamics in the presence of cavity HOMs, BBU and other halo studies, handling of large (SR induced) momentum spread bunches, and development of multiple-beam diagnostics instrumentation. Figure 1: 12 GeV CEBAF recirculating linac. Location of chicane and dump line for ER@CEBAF. Since it was launched 2+ years ago, the project has progressed in defining the necessary modifications to CEBAF (Fig. 1, Tab. 1, 2), including a 4-dipole phase chicane in recirculation Arc A, beam extraction and a dump line at the end of the south linac, and additional dedicated multiplebeam diagnostics. This equipment can remain in place to Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, † and by Jefferson Science Associates, LLC under Contract No. DEAC05-06OR23177 with the U.S. Department of Energy. ‡ Spokesperson. fmeot@bnl.gov; satogata@jlab.org Table 1: Machine/Lattice Parameters of ER@CEBAF fRF 1497 MHz RF frequency Elinac 700 MeV Gain per linac (baseline) Einj 79 MeV = Elinac × 123/1090 φFODO 60 deg Per cell, at first NL pass and last SL pass M56 <90 cm Compression, Arc A Extraction 8 deg Angle to dump line

Muon RLA – design status and simulations

The Neutrino Factory baseline design involves a complex chain of accelerators beginning with a linac. This first pre-linac follows the capture and bunching section and accelerates the muons from about 244 to 900 MeV and must accept a high emittance beam about 30 cm wide with a 10% energy spread. It uses counterwound, shielded superconducting solenoids and 201 MHz superconducting cavities, and currently consists of 24 3 m and 24 5 m long cryomodules. The next stage is a 1st dogbone-shaped RLA that takes the total energy from 900 MeV to 3.6 GeV in 4.5 passes, followed by a 2nd RLA that takes the energy from 3.6 to 12.6 GeV in 4.5 passes. Simulations are in progress to optimize the optics and determine the radiation loads from beam loss and muon decay.