Speaker
Filip Grepl
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.2032.pdf
Optical probing during an experiment on proton acceleration from a
cryogenic hydrogen ribbon
F. Grepl1,2 , D. Margarone1 , H. Ahmed4 , A. Alejo4 , P. Bonnay5 , D.C. Carroll6 ,
D. Chatain5 , D. Doria4 , D. Garcia5 , A. Girard5 , L. Giuffrida2 , P. Jones6 , P. Lutoslawski1 ,
P. Martin4 , S. Michaux5 , B. Odlozilik1,2 , F. Schillaci2 , V. Scuderi3 ,
A. Velyhan2 , F. Viargues5 , D. Neely6 , G. Korn1 and M. Borghesi4
1 Institute of Physics ASCR, ELI Beamlines Project, Prague, Czech Republic
2 Czech Technical University in Prague, FNSPE, Prague, Czech Republic
3 Istituto Nazionale di Fisica Nucleare, LNS, Catania, Italy
4 Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast,
Belfast, United Kingdom
5 CEA INAC-SBT, Grenoble, France
6 Central Laser Facility, Rutherford Appleton Laboratory, Didcot, United Kingdom
Multidisciplinary applications of laser-driven ion beams, especially medical ones, have strict
requirements for ion beam parameters. Some of them can be achieved by using a specially
tailored target. In particular, pure proton beams (without contaminants) can be produced from
cryogenic solid-hydrogen targets which could be capable of both refreshable and debris free
operation at high repetition rate making this target ideal for laser-based protontherapy.
This contribution reports acceleration of protons from relatively thin (75 and 100 µm) solid-
hydrogen ribbon employing the petawatt arm of the VULCAN laser at Rutherford Appleton
Laboratory with emphasis given on optical probing of the unstable ribbon target. Firstly, optical
probing was used for characterizing the ribbon itself, and the laser focus position with respect
to the target front surface. Obtained data are directly correlated with the energy of forward
accelerated ions measured with radiochromic films and Thomson parabola ion spectrometer.
In addition, the electron density distributions of hydrogen plasma are presented after being
retrieved from interferometry snapshots taken with various delays with respect to the arrival of
the main laser pulse.
Monoenergetic features observed in the energy spectra measured with Thomson parabola ion
spectrometer and radiochromic films stack will be also presented and compared with supporting
PIC simulations with aim to explain the features origin.
