Shortly after, LLNL scientist George Maenchen circulated a memo noting that the instrument used to measure the laser output was subject to interactions with the explosion. The system worked by measuring the brightness of a series of beryllium reflectors when they were illuminated by the lasers. Maenchen noted that the reflectors themselves could give off their own signals when heated by the bomb, and unless they were separately calibrated, there was no way to know if the signal was from the laser or the bomb. This calibration had not been carried out, rendering the results of all of these tests effectively useless.