The mobile unit for neutron detection (MUND) is an all in one neutron detection system for data collection and storage that is capable of running on battery power. The unit is based on a 3He detector mounted inside a polyethylene moderator slab and integrated with all the supporting electronics inside a single, sealable enclosure. Once installed, a MUND is usually serviced by replacing the unit with a fully recharged one. The MUND collects data for more than eight weeks without service.

(Source: IAEA Safeguards Techniques and Equipment)