We present spin-exchange optical pumping (SEOP) using a third-generation (GEN-3) automated batch-mode clinicalscale 129 Xe hyperpolarizer utilizing continuous high-power (∼170 W) pump laser irradiation and a novel aluminum jacket design for rapid temperature ramping of xenon-rich gas mixtures (up to 2 atm partial pressure). The aluminum jacket design is capable of heating SEOP cells from ambient temperature (typically 25°C) to 70°C (temperature of the SEOP process) in 4 min, and perform cooling of the cell to the temperature at which the hyperpolarized gas mixture can be released from the hyperpolarizer (with negligible amounts of Rb metal leaving the cell) in approximately 4 min, substantially faster (by a factor of 6) than previous hyperpolarizer designs relying on air heat exchange. These reductions in temperature cycling time will likely be highly advantageous for the overall increase of production rates of batch-mode (i.e., stopped-flow) 129 Xe hyperpolarizers, which is particularly beneficial for clinical applications. The additional advantage of the presented design is significantly improved thermal management of the SEOP cell. Accompanying the heating jacket design and performance, we also evaluate the repeatability of SEOP experiments conducted using this new architecture, and present typically achievable hyperpolarization levels exceeding 40% at exponential build-up rates on the order of 0.1 min −1 .
Prof. Eduard Y. Chekmenev received his PhD in Physical Chemistry (supervisor Prof. Richard J. Wittebort) in 2003 at the University of Louisville, KY (USA). He conducted postdoctoral research at the National High Magnetic Field Laboratory in Tallahassee, FL (with Prof. Timothy Cross), Caltech (Prof. Daniel P. Weitekamp) and HMRI in Pasadena, CA (USA) (with Dr.B rian D. Ross). In 2009, Dr.C hekmenev started his hyperpolarization program at Vanderbilt University (Nashville, TN) and he was tenured in 2015. In 2018, he moved to Wayne State University (Detroit, MI) to continue his research on MR hyperpolarization.Figure 1. Thermal equilibrium polarizationp roduces asmall excess of spins in one state. When the sample undergoes hyperpolarization, alarge excess of spins exists in one state producingaconsiderably stronger signal since more spins contribute.
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