Advanced active interrogation sources for remote detection of special nuclear material
AWE has recently commenced a research programme to develop techniques for the remote detection of illicitly trafficked, special nuclear material. Three techniques that are being investigated as part of this programme utilise an active interrogation source to stimulate a radiation signature within SNM. A photonuclear technique and nuclear resonance fluorescence require an active gamma source while a technique stimulating fission with low energy neutrons requires a low energy neutron source. The potential for consolidation of the photonuclear and neutron technique is discussed. Conceptual designs of intense, pulsed, ion beam diodes to generate suitable sources of 6-7MeV gamma photons for the photonuclear technique and ≪100keV neutron sources for the active neutron technique are presented. The sources required for remote detection via the 60keV neutron or photofission techniques are contrasted with the source requirements for nuclear resonance fluorescence.
Active detection of small quantities of shielded highly-enriched uranium using low-dose 60-kev neutron interrogation
Abstract Active interrogation with low-energy neutrons provides a search technique for highly-enriched uranium concealed in cargo. We describe the technique and show initial results using a low-dose 60-keV neutron beam. This technique produces a clear induced fission signal in the presence of small quantities of 235 U. The technique has been validated with low-Z and high-Z cargo materials. The technique uses a forward-directed beam of 60-keV neutrons to induce fission in 235 U. Detection of the fast fission neutrons with pulse-shape discriminating scintillators is then the signature for 235 U. The beam of neutrons is generated with a 1.93 MeV proton beam impinging on a natural lithium target. The proton beam is produced by a radio-frequency quadrupole LINAC. The 60 keV neutron beam is forward-directed because the 7 Li(p, n) reaction is just above threshold for a proton energy of 1.93 MeV.
Acetylation analysis of saccharides. 2. Microanalysis of neutral glycosphingolipids by means of acetylation with radioactive acetic anhydride.
Abstract The quantitative analysis of mixtures of glycosphingolipids by acetylation with radioactive acetic anhydride and separation by thin-layer chromatography is described. The method was primarily developed for screening of glycosphingolipid composition of tissues, cultured cells, and virus preparations. The sensitivity and linearity of the method is demonstrated. Although theoretically a much higher sensitivity is achievable, in practive about 10 −9 g of glycosphingolipid can be detected and tentatively identified. As an example, the acetylation pattern of lipids from a preparation of herpes simplex virus is demonstrated.