Two-dimensional gas micro-well detector fabricated using advanced processing technology (3-DTI, MWD)

The Three-Dimensional Track Imager (3-DTI), developed at NASA Goddard Space Flight Center, is the enabling technology for future astrophysics missions. Using advanced technology, we propose to develop a process to fabricate a two-dimensional micro-well detector (MWD) readout for the 3-DTI.  The MWD will provide tremendous improvements in 3-DTI reliability and performance.

The gas filled 3-DTI Time Projection Chamber (TPC) achieves high particle track resolution using a negative ion (NI) drift technique to reduce diffusion of the ionization electrons along the track of a charged particle.  This technique allows the track information to be preserved over long drift distances.  The negative ion (NI) technique, however, presents a challenge to the TPC readout which typically utilizes a Townsend avalanche to amplify and detect the ionization charge. Using the NI technique, the ionization electron must be knocked free from the electronegative molecule before the Townsend avalanche can occur. This work utilizes advanced material processing techniques to fabricate small, high gain MWD structures.  In addition, the small features reduces any loss of active area due to MWD tiling can be reduced to nearly zero and outgassing concern eliminated by using inorganic insulator and support materials.