The Forward Tagger facility for lowQ2experiments at Jefferson Laboratory

Andrea Celentano

doi:10.1051/epjconf/20147308004

Abstract

Low Q2 electron scattering is an efficient and competitive experimental technique to provide intense, quasi-real photon beams, with a high degree of linear polarization. Such a technique will be employed in Hall B at Jefferson Laboratory by having the primary 11 GeV electron beam from the CEBAF accelerator impinging on a liquid hydrogen target. Low-angle scattered electrons will be detected with the new Forward Tagger facility, while the final state hadrons will be measured with the CLAS12 spectrometer. The unique combination of the two detectors will permit to carry out a broad physics program, and to explore new possibilities for high quality physics.

Highlights

Low Q2 electron scattering provides an alternative to real photoproduction to produce intense photon beams, with high energy and high degree of linear polarization
Low Q2 electron scattering is an efficient and competitive experimental technique to provide intense, quasi-real photon beams, with a high degree of linear polarization. Such a technique will be employed in Hall B at Jefferson Laboratory by having the primary 11 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator impinging on a liquid hydrogen target
The unique combination of the two detectors will permit to carry out a broad physics program, and to explore new possibilities for high quality physics

Summary

Introduction

Low Q2 electron scattering provides an alternative to real photoproduction to produce intense photon beams, with high energy and high degree of linear polarization. The expected rate of hadronic events, at the CLAS12 nominal luminosity (1035 cm−2 s−1), is about 7 KHz: this corresponds to an equivalent photon flux of about 5 · 107 /s, for a “traditional” photo-production experiment employing a 40 cm-long LH2 target. This value is comparable to the photon fluxes of present real photo-production experiments, such as GlueX at Jefferson Laboratory

Jefferson Laboratory

The Forward Tagger Facility

FT-Cal

FT-Hodo

Conclusions