Matching the laser generatedpbunch into a crossbar-Hdrift tube linac

Abstract

Proton bunches with energies up to 30 MeV have been measured at the PHELIX laser. Because of the laser-plasma interactions at a power density of about 4 Â 10 19 W=cm 2 , a total yield of 1:5 Â 10 13 protons was produced. For the reference energy of 10 MeV, the yield within AE0:5 MeV was exceeding 10 10 protons. The important topic for a further acceleration of the laser generated bunch is the matching into the acceptance of an rf accelerator stage. With respect to the high space charge forces and the transit energy range, only drift tube linacs seem adequate for this purpose. A crossbar H-type (CH) cavity was chosen as the linac structure. Optimum emittance values for the linac injection are compared with the available laser generated beam parameters. Options for beam matching into a CH structure by a pulsed magnetic solenoid and by using the simulation codes LASIN and LORASR are presented.

Focusing and transport of high-intensity multi-MeV proton bunches from a compact laser-driven source

“…Over the past years, numerous experimental investigations on the different facets of TNSA as well as simulation studies and theoretical approaches [4,5] contributed to the deeper understanding of the mechanism and increasingly raised interest in the field. There is a wide and growing range of applications for these beams, e.g., already today the creation of warm dense matter [6][7][8], proton imaging [9], or the creation of bright neutron sources [10,11], and possibly in the future proton fast ignition [12], clinical applications [13,14], or high-intensity ion sources in general, in some cases combined with a postacceleration stage [15,16]. Special interest is given to the application as a diagnostic tool for high density matter, which is foreseen for experiments of the HEDgeHOB collaboration at the FAIR facility [17].…”

Performance of solenoids versus quadrupoles in focusing and energy selection of laser accelerated protons

“…The role of space charge and geometric aberrationsdominant for short solenoids -needs further consideration even though they are not expected to alter the major conclusions. Noting that solenoid focusing is independent of the charge, the neutralizing co-moving electrons, which are always present in laser acceleration, will be strongly focussed towards the axis [28]. In the triplet, instead, these electrons will be de-focussed to the aperture when entering the first quadrupole, which may have an effect on the quality of focusing and needs to be further explored.…”