sentences:  In the case of HiPER, the driver laser system is similar to existing systems like NIF, but considerably smaller and less powerful.The driver consists of a number of "beamlines" containing amplifiers at one end of the building.Just prior to firing, the glass is "pumped" to a high-energy state with a series of xenon flash tubes, causing a population inversion of the neodymium (Nd) atoms in the glass.