[en] Lasers can interact electrons with electrons in several ways. With a 90 degrees crossing angle the laser can be used as an unbreakable wire that will generate Compton scattering and allow the measurement of electron beams that are only a few micrometers wide. Compton scattering is also used when the beams collide head on to generate intense X-rays or γ-rays as was done in the Mighty Laser experiment. Building a dedicated accelerator for this purpose will make a compact X-ray source, as in the ThomX project. Finally if the photons are co-propagating with the electrons in a plasma they create a wakefield that will accelerate the electrons with very high gradients, creating the need for new diagnostics for these electrons. I have worked on projects using these different configurations. In this manuscript I describe my work on these projects. (author)

[en] The design of a stripline kicker with a movable electrode for the FEATHER project is detailed here. More than 1000 simulations have been done with the POISSON/SUPERFISH code to study the impedance of various electrostatic configurations. (author)

[en] To increase the energy of particles supplied by accelerators to reach the requirements of the Linear Collider or of the Super KEK-B factory, new accelerating structures with a higher accelerating gradient need to be developed. These accelerating structures are often affected by high power breakdowns. Knowing the exact location where these breakdowns occurred helps to redesign the structure and improve its performances. This can be done with acoustic sensors. (author)

[en] Ground motion at the Future JLC (Joint Linear Collider) detector may affect beam alignment and cause huge luminosity loss. The FEATHER (FEedback AT High Energy Requirements) project addresses this problem by designing a fast intra-pulse feedback system that will correct the observed beam offset. (author)

[en] A new laser-wire is being installed in the extraction line of the ATF at KEK. This device aims at demonstrating that laser-wires can be used to measure micrometre scale beam size. (author)

[en] In this paper, we derive the cross section formula for the Higgs pair production at a linear e⁺e^- collider in models with large extra dimensions and study the feasibility of its measurement through realistic Monte Carlo simulations. Since the process has essentially no standard model background, once produced, it will provide us with a very clean signature of physics beyond the standard model. Moreover, since the final-state particles are spinless, the spin-2 of the intermediate virtual Kaluza-Klein (KK) gravitons has to be conserved by the orbital angular momentum of the Higgs pair. This results in a very characteristic angular distribution of the final states. Taking into account finite detector acceptance and resolutions as well as initial-state radiation and beamstrahlung, we demonstrate in this paper that, given a sufficiently high center of mass energy, the angular distribution of the Higgs pair is indeed measurable at the linear collider and will allow us to prove the spin-2 nature of the KK gravitons exchanged in the s channel

[en] We present a pepper-pot design in which we address the problem of penetration by high energy particle, deriving analytical expressions and performing GEANT4 simulations for the estimation of the error introduced by a long (thick) pepper-pot. We also show that a careful design allows to measure the emittance of electron beam of several hundreds MeV and beyond.

[en] A new laser-wire is being installed in the extraction line of the ATF at KEK. This device aims at demonstrating that laser-wires can be used to measure micrometre scale beam size

[en] The ESCULAP project aims at studying external injection of low energy (10 MeV) electrons in a plasma in the quasilinear regime. This facility will use the photo injector PHIL and the high power laser LASERIX. We will give a status report of the preliminary work on the facility and the status of the two machines. We will also present the results of simulations showing the expected performances of the facility.

[en] We present the first measurement of the transverse emittance of an electron bunch at 3 GeV using the pepper-pot technique. The measurements presented in this paper demonstrate the possibility to use such a method for single shot emittance measurement of high energy particles. This measurement presents also the experimental verification of a previous theoretical study, which was predicting in which condition such a measurement can be done. The method may present some technical limitations which are discussed in view of the application to future very small emittance multi-GeV particle accelerators