Study on Mems Glassblown Cells for NMR Sensors

This paper presents a study on factors that affect the relaxation rates of noble gas atoms in miniaturized atomic vapor cells of Nuclear Magnetic Resonance (NMR) sensors. The cells are implemented using the micro-glassblowing process, [1]. Our study is focused on the cell construction material and the inner wall coating of the cells. We showed that the wafer-level coating process with Al2O3 increased the 131Xe relaxation time (T2) by 4x and by switching from Borosilicate glass (Pyrex) to Aluminosilicate glass (ASG) T2 improved by 3x, for the same species. The improvement in T2 is projected to reduce the ARW of an NMR gyro by 4x and 3x with Al2O3 coated cells and ASG cells, respectively.