This paper describes the design and simulation of a radiation detector system for diagnostic measurements of photon beams produced by Thomson or Compton Scattering. The photon beam is Compton scattered in a thin passive converter, and the resulting electrons are analyzed using a charge-coupled device-based tracker and classification algorithms. The flux of the scattered electrons is much lower than that of the photon beam and is additionally dispersed. This dispersal enables measurements while avoiding pileup, which is important in order to provide diagnostic information from intense 'shot' based pulsed systems, such as those being built to leverage laser wakefield accelerators. Simulations indicate that the designed system is capable of resolving beam parameters from a single shot. The fidelity to which various beam parameters can be resolved is presented as are methods that could result in further improvement to diagnostic resolution.

Gold nanoparticles can be used as ultimate electrical materials for storing electrons or controlling their flow for the next generation nano-electronic devices. These particles are the core element of assemblies where the electrical current is reduced to the smallest possible since electrons are controlled one by one by using the Coulomb blockade phenomenon. We prepared colloidal gold nanoparticles beteween 4 and 15 nm and grafted them on a grafted organic monolayer (GOM) on silicon. GOM are highly ordered monolayers prepared by hydrosilylation of alkene molecules and subsequently modified with an amine group so that gold nanoparticles can be firmly immobilized on top of the layer. We discuss several electrical properties at a single electron level. Using the conductive tip of KPFM, we were also able to reveal the spontaneous charging behavior of the gold nanoparticles so that the local work function of a 10 nm gold nanoparticle is only 3.7 eV. By placing an STM tip above a nanoparticle, Coulomb blockade allows controlling the number of electrons simultaneously injected in the nanoparticle. This opens the way for new kinds of single electron memories or single electron transistors.

No abstract