Neutron flux measurements are important in fusion devices for both safety requirements and physics studies. A newsystem has been built for the Mega Amp Spherical Tokamak Upgrade (MAST Upgrade) that provides neutron count,DC and Campbell mode measurements for a 1μsperiod at 1 MHz. The acquisition system uses a Red Pitaya board tosample current from two fission chambers mounted on the side of the MAST-U vessel. The system-on-chip design ofthe Zynq-7020 on the Red Pitaya also allows a web server implementation using Flask for data retrieval and diagnosticconfiguration over the MAST-Upgrade network.