TACTIC: a detector for nuclear astrophysics featuring Soham Chakraborty (TRIUMF)

Note: This seminar will take place 2:30pm-3:30pm Eastern Time

Hosted by: Cameron Angus (TRIUMF)

Abstract: TACTIC is a cylindrical active target time projection chamber, jointly developed by the University of York and TRIUMF. The detector facility is suitable for the direct measurement of alpha-induced charged particle reactions, important for understanding nucleosynthesis in different cosmic environments. The reaction cross section measurements rely on the tracking, detection, and identification of the reaction products by means of differential energy loss in the gaseous detection volume. In order to detect the reaction products over a wide range of energies (tens of keV to a few MeV), the novel μ-RWELL (micro-Resistive WELL) detectors are used in TACTIC as the gas multiplication stage. An unique central cathode cage configuration enables the detector to accommodate higher beam intensities (in the order of 10^7 pps) compared to other active target detectors. This specific feature, combined with a high detection efficiency, allows the measurements of low cross sections (in the order of μb) utilising radioactive ion beams in the astrophysically important energy regions of interest. The first successful cross section measurement using TACTIC was performed in 2022 at the TRIUMF ISAC-I facility. The astrophysically important and experimentally well-constrained 23Na(⍺, p)26Mg reaction was studied as a commissioning experiment. Prior to their installation in TACTIC, a detailed characterisation of the μ-RWELL detectors in different gas mixtures and pressures was performed utilising a planar test chamber. The installation marked the very first integration of the state-of-the-art μ-RWELL detectors inside a cylindrical geometry for charged particle tracking. I will discuss the results from the test chamber and TACTIC tests as well as the planned future developments.