近物所学术报告: Active target system for medium-energy high-intensity heavy-ion beams
报告题目：CAT: Active target system for medium-energy high-intensity heavy-ion beams
报告人：Shinsuke OTA博士 (东京大学CNS)
摘要：Traditional nuclear reactions such as inelastic scattering of proton, deuteron, andhelium, or transfer reactions starting from proton, deuteron, helium are powerfulspectroscopic tools to study not only the nuclear structures and dynamics but alsothe nuclear matter equation of state. These reactions are now adopted in the study ofunstable nuclei in the manner of so-called inverse kinematics, where physics objectis beam and probe is target. In combination with missing-mass spectroscopy ininverse kinematics, it is difficult to measure very forward angle scattering in inelasticscattering or the reaction with helium because the thick target cannot be used there.Active target technique, where the filled gas simultaneously acts as the target andthe detector gas, is efficient for such reactions since the target can be thick withkeeping the resolutions.
Our motivation of the active target development is to measure the isoscalar giantmonopole resonances in Tin-region unstable nuclei via deuteron inelastic scatteringfor the clarification of nuclear matter EoS. Our active target can be widely usedfor many other nuclear reaction measurements.. Recently, in 2017, an active targetsystem CAT-M having 28×32×20-cm3 active volume has been constructed by CNSin collaboration with some other institutes and universities, to increase the luminosity by factor of five and the acceptance by more than double of CAT-S having10×10×25-cm3 active volume, developed by CNS, too. These active targets havedifferences in their size but they have common remarkable feature such as simultaneous accessibility to the high-intensity up to 1 Mcps, large-mass more than 130and medium-energy more than 100 MeV/u. This accessibility meets the conditionassumed for the coming high-intensity facility HIAF and the possible upgrade ofexisting facility RIBF. The key point of our active targets in the structure is thecombination of the dual-gain THGEM operation and the regular triangle readoutpad.
In this talk, possible implementation of TPC for the nuclear reactions withintermediate-energy high-intensity beams will be discussed. Then the design andperformance evaluation of CAT-S and CAT-M will be introduced together with thebrief summary of recent result of deuteron inelastic scattering off Tin-region unstablenuclei.