The University of Cambridge has facilities for fabrication of GaAs electron pumps (molecular beam epitaxy, GaAs processing cleanroom, electron beam lithography) and low-temperature measurements of these devices. The Semiconductor Physics group at the University of Cambridge has collaborated with NPL in the development of single-electron current sources since 2007, most recently with SIB07-REG2 of EMRP JRP SIB07 Qu-Ampere. This group have expertise in fabricating multiplexed arrays of mesoscopic GaAs devices. In this project they will perform device fabrication and characterisation of GaAs pump arrays. University of Cambridge, Semiconductor Physics Dept.