Experiment E12-15-008 will measure 40ΛK and 48ΛK hypernuclei to investigate the isospin dependence of the ΛNN interaction at Jefferson Lab Hall A.
Left figure shows a schematic of the experimental setup. An electron beam of Ee = 4.5 GeV will be incident on a target to produce Λ hypernuclei through the (e,e'K+) reaction. The scatterd electron and K+ with momenta of 3.0 and 1.2 GeV/c will be momentum-analyzed by two existing-magnetic spectrometers, HRS and HKS, respectively.
We are now designing a new septum magnet (SEP) that leads to smaller-scattering angle coverages for both e' and K+. Particle detections at the small scattering angle are needed to increase a virtual photon flux and to cover a region with a larger differential-cross section of the (γ*,K+) reaction.
A target system, that allows us to use isotopically enriched targets of 40Ca and 48Ca in a vacuum chamber, is also being designed. The targets need a cooling system becasue the heat due to an energy deposite of the high current electron beam (∼50 μA) cannot be removed by convection in the vacuum environment.