“…pH 2 fraction, f pH 2 , of 90 % and above is produced by PHGs with single-or dual-stage cryostats run by helium compres- (Hövener et al, 2013), (3) (Feng et al, 2012), (4) HyperSpin-PHG (Meier et al, 2019), (5) automated PHG (Birchall et al, 2020), (6) He-dewar PHG (Du et al, 2020), (7) U-shaped PHG (Kiryutin et al, 2017), (8) economical PHG (Jeong et al, 2018), ( 9) glass-trap PHG (Gamliel et al, 2010) (Haynes, 2011). All these PHGs were specifically designed with PHIP (parahydrogeninduced polarization) in mind, meaning for a relatively low scale of production and in-lab use (not for industry).…”