 The Advanced Virgo aims to be 10 times more sensitive than the initial Virgo.According to the Advanced Virgo Technical Design Report VIR–0128A–12 of 2012, advanced Virgo keeps the same vacuum infrastructure as Virgo, with four additional cryotraps located at both ends of both three-kilometre-long arms to trap residual particles coming from the mirror towers, but the remainder of the interferometer has been significantly upgraded.The new mirrors are larger (350 mm in diameter, with a weight of 40 kg), and their optical performances have been improved.