Relatore
Sig.
Ikeda Tomonori
(Kobe University)
Descrizione
Negative-ion TPCs have been studied for low-rate and high-resolution applications. Lately, the discovery of "minority carriers" in CS2 gas, broadened its potential and the measurement of absolute Z-position in a self-triggering TPC became possible (J.B.R. Battat et al., (2014) arXiv:1410.7821). The minority carriers appeared after adding a few percent O2 to the original gas. They each drift with slightly different velocities. Recently, a GEM-TPC with SF6 negative ion drift gas was reported (Nguyen Phan, Eric Lee in: Cygnus 2015 Conference in Los Angeles). They also observed minority carriers without any additional gas. SF6 is non-toxic, it can be handled easily while keeping the same advantages as CS2 gas.
NEWAGE has been using a μ-PIC-based TPC for direction-sensitive dark matter search using CF4 gas (Nakamura et.al, PTEP(2015)043F01s). In order to increase the angular resolution and decrease the radioactive background, we started a new study using a uPIC-based TPC with negative ion gas. A test performed at Occidental College showed that a uPIC system with pure CS2 gas can have a gain as high as with pure CF4 gas. This was the first test of negative ion gas with a μ-PIC. We plan to test a μ-PIC-based TPC with SF6 gas. We will optimize the SF6 gas mixture and pressure for dark matter detection. Minority peaks in SF6 will be used to achieve full volume fiducialization without an external start pulse and should be a valuable tool for rare-event detection such as in Dark Matter Experiments.
Autore principale
Sig.
Ikeda Tomonori
(Kobe University)
Coautore
Dr.
Gauvreau Jean-Luc
(Occidental College)
Prof.
Snowden-Ifft Daniel
(Physics Department Occidental College)
