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.
Gamma-ray compton light source development at LLNL
A new class of tunable, monochromatic λ-ray sources capable of operating at high peak and average brightness is currently being developed at LLNL for nuclear photo-science and applications. These novel systems are based on Compton scattering of laser photons by a high brightness relativistic electron beam produced by an rf photoinjector. A prototype, capable of producing ≫ 108 0.7 MeV photons in a single shot, with a fractional bandwidth of 1%, and a repetition rate of 10 Hz, is currently under construction at LLNL; this system will be used to perform nuclear resonance fluorescence experiments. A new symmetrized S-band rf gun, using a Mg photocathode, will produce up to 1 nC of charge in an 8 ps bunch, with a normalized emittance modeled at 0.8 mm.mrad; electrons are subsequently accelerated up to 120 MeV to interact with a 500 mJ, 10 ps, 355 nm laser pulse and generate γ-rays. The laser front end is a fiber-based system, using corrugated-fiber Bragg gratings for stretching, and drives both the frequency-quadrupled photocathode illumination laser and the Nd:YAG interaction laser. Two new technologies are used in the laser: a hyper-Michelson temporal pulse stacker capable of producing 8 ps square UV pulses, and a hyper-dispersion compressor for the interaction laser. Other key technologies, basic scaling laws, and recent experimental results will also be presented, along with an overview of future research and development directions.
The National PKI of Peru: a new certification hierarchy
In order to guarantee secure transactions through the Internet and to generate strong evidence that could be used in case of future legal disputes, several countries around the world have promoted and regulated the use of digital signatures based on Public Key Infrastructure (PKI). However, despite the high expectations, its implementation has achieved neither the desired results nor its globalization. Many of the reasons were discovered years ago, but they are still open problems for the scientific community nowadays. In order to consider the case of the national PKI of the Peruvian state as empirical evidence for studies that address the open problems, this article describes the details about a new certification hierarchy which is expected to overcome some of its predecessors’ limitations. It is also expected that the information disclosed in this article could be useful to other countries for making a preliminary assessment for possible cross-border recognition of Peruvian digital signatures.