The 3777 upgrade module provides a straightforward means to enhance 129Xe polarization on existing 9800 system by up to a factor of two. Such a doubling of high-purity, hyperpolarized 129Xe polarization improves gas phase magnetic resonance studies by increasing imaging SNR, accelerating workflow or decreasing the volume of xenon required for a study.
The upgrade package replaces a number of critical components in the standard 9800 system with higher performance designs to enable 129Xe polarization levels in the range of 20-25% at typical production throughput. This objective is achieved via a combination of enhancing xenon polarization within the optical cell using the existing laser source in 9800 system, and reducing polarization loss in cryogenic collection and recovery of hyperpolarized 129Xe.
129Xe polarization as a function of production rate after installing the 3777 upgrade module 129Xe polarization levels in the range of 20-25% are achievable using the standard 60W laser installed on 9800 systems. The dashed line shows the 129Xe polarization leaving the cell whereas the color coded lines depict the collected xenon volume using an effective solid-state xenon relaxation time of one hour.
Operation of the upgraded polarizer remains identical to that of the standard 9800 system, while bringing key displays and valves to a more ergonomic location. The upgraded system continues operating as a Class 1 laser system, and thus requires no laser protective eyewear during normal operation.
The new central control unit replaces the conventional temperature / interlock controller. In addition to providing the legacy functions, it regulates the rubidium presaturator function and provides enhanced monitoring and control of laser light transmission
The improved magnetic holding field minimizes polarization loss during xenon collection and recovery, and prolongs the polarization retention in solidstate xenon.
An integral part of the polarized xenon collection system is the enhanced cryogenic trap the cold finger, featuring an optimized geometry to enhance xenon freezing pattern and retention. This new design leads to a higher ultimate polari-zation of xenon through a longer solid-state relaxation time and an accelerated thaw into gas state.
The new optical cell design incorporates a pair of optical quality flat windows, a reinforced rubidium pre-saturator and a dedicated heater. The cell body is now largely free from rubidium and operates at a lower temperature than the rubidium pre-saturator in order to maximize spin exchange efficiency.
The 9800 Xenon Hyperpolarization System and the associated upgrades are designed for research use. When used to produce hyperpolarized xenon for human inhalation, all applicable institutional and federal approvals must be obtained.