On January 28, 2010, NIF reported the delivery of a 669 kJ pulse to a gold hohlraum, breaking records for laser power delivery, and analysis suggested that suspected interference by generated plasma would not be a problem in igniting a fusion reaction. Due to the size of the test hohlraums, laser/plasma interactions produced plasma-optics gratings, acting like tiny prisms, which produced symmetric X-ray drive on the capsule inside the hohlraum. After gradually altering the wavelength of the laser, scientists compressed a spherical capsule evenly and heated it to 3.3 million kelvins (285 eV). The capsule contained cryogenically cooled gas, acting as a substitute for the deuterium and tritium fuel capsules to be used later. Plasma Physics Group Leader Siegfried Glenzer said that they could maintain the precise fuel layers needed in the lab, but not yet within the laser system. As of January 2010, the NIF reached 1.8 megajoules. The target chamber then needed to be equipped with shields to block neutrons. National Ignition Campaign 2010–2012 With the main construction complete, NIF started its National Ignition Campaign (NIC) to reach ignition. At the time, articles appeared in science magazines stating that ignition was imminent. Scientific American opened a 2010 review article with the statement "Ignition is close now. Within a year or two..." The first test was carried out on October 8, 2010, at slightly over 1 MJ. However, problems slowed the drive toward ignition-level laser energies in the 1.4–1.5 MJ range. One problem was the potential for damage from overheating due to a greater concentration of energy on optical components. Other issues included problems layering the fuel inside the target, and minute quantities of dust on the capsule surface. The power level continued to increase and targets became more sophisticated. Then minute amounts of water vapor appeared in the target chamber and froze to the windows on the ends of the hohlraums, causing an asymmetric implosion. This was solved by adding a second layer of glass on either end, in effect creating a storm window. Shots halted from February to April 2011, to conduct SSMP materials experiments. Then, NIF was upgraded, improving diagnostic and measurement instruments. The Advanced Radiographic Capability (ARC) system was added, which uses 4 of the NIF's 192 beams as a backlight for imaging the implosion sequence. ARC is essentially a petawatt-class laser with peak power exceeding a quadrillion (1015) watts. It is designed to produce