Liquid helium of liquid water. Helium was first liquefied on July 10, 1908, by the Dutch physicist Heike Kamerlingh Onnes at the University of Leiden in the Netherlands. At that time, helium-3 was unknown because the mass spectrometer had not yet been invented. In more recent decades, liquid helium has been used as a cryogenic refrigerant, and liquid helium is produced commercially for use in superconducting magnets such as those used in magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), Magnetoencephalography (MEG), and experiments in physics, such as low temperature Mössbauer spectroscopy. The temperature required to produce liquid helium is low because
Leiden Law School result of this policy, the old Kamerlingh Onnes Laboratory, named after physicist Heike Kamerlingh Onnes, was restyled into a new home for the law school; the move was completed in 2004. A reorganisation of the faculty, which began in the 1980s, realigned the faculty's focus to major fields such as civil, corporate, notarial, criminal, European and international law; these areas remain Leiden's traditional areas of scholarly strength. The Cleveringa Institute was established in 2001 to maintain the integrity of teaching and intellectual rigour in courses. The faculty's research was moved to the E.M. Meijers Institute in 1997 and emphasised interdisciplinary