21. Neutron porosity logging tools contain an americium-beryllium neutron source , which irradiates the formation with neutrons. 22. Radium tetrafluoroberyllate is used as a standard neutron source . 23. The secondary consists of LiD fuel, which requires an external neutron source to begin the reaction. 24. Since 1976 he has been working at the Forschungszentrum J�lich, doing research on spallation neutron sources . 25. This way a long-lived neutron source is produced. 26. None of the commonly available neutron sources are adequate for fusion materials testing for various reasons. 27. For nuclear weapons applications, dense plasma focus devices can be used as an external neutron source . 28. The best-known neutron sources were radium-beryllium and polonium-beryllium. 29. He says the Spallation Neutron Source will restore U . S . leadership in the field. 30. It is practiced at research reactors and spallation neutron sources that provide neutron radiation of sufficient excitations.
