New Negative Ion Time Projection Chamber Technology for Directional Detection of Dark Matter, Neutrinos and Fast Neutrons

Low energy nuclear recoils are one of the few signatures of the passage of WIMPs, fast neutrons and neutrinos though matter. The directional information encoded in the nuclear recoils provides valuable data which is otherwise inaccessible to a particle detector. Gas TPCs are one of the few technologies capable of reconstructing a low energy nuclear recoil track well enough to extract directional information. Scaling TPCs to large volumes while maintaining a low energy threshold and good position resolution is vital for these applications where the rarity of the interactions with matter can only be offset with larger target mass.
This work focuses on amplification, charge collection and readout technologies which are able to achieve a low energy threshold on the order of keV in negative ion gases and which have the potential to scale to large areas. Initially the gain and energy resolution of the ThGEM device is determined in low pressure SF6. Results for the first operation of the novel MM-ThGEM amplification device in a negative ion drift gas are presented, showing that the device overcomes a number of problems encountered with the ThGEM while maintaining good gain in SF6. A resistive layer micromegas is used to achieve three dimensional reconstruction of events in combination with the MM-THGEM which is shown to be necessary to obtain overall gas gains sufficient to achieve a low energy threshold. The MMThGEM-micromegas is shown to work well in combination with the scalable Kobe NI-DAQ electronics and to be sensitive to alpha particles, x-rays, neutrons and gamma rays. The results indicate that the novel technology is a promising avenue of development towards a large directional nuclear recoil detector. A study of the feasibility of a gas TPC experiment aiming to observe the CEνNS scattering of reactor neutrinos is also presented for the first time.