Gordon Freeman was the scientist responsible for inserting the sample for analysis. The scientists admitted that it was 'a bit of a gamble,' but they needed extra resolution for the analysis. Seeing this as a rare opportunity to gain priceless data, they boosted the anti-mass spectrometer to 105% power, much higher than the equipment's safety buffer zone of below 90%. It is implied in Half-Life 2 Episode 2 that the G-Man presented this crystal to the scientists. The GG-3883 sample was, in addition to being the purest, also the most unstable sample that Sector C staff experimented on. The experiment was supposed to analyze the purest sample of Xen crystals, procured by expedition teams in the borderworld. The Black Mesa Incident was caused directly by an experiment in the Sector C C/33a Test Chamber. The cause of the Black Mesa incident - The Anti-Mass Spectrometer.
